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Sample records for leg muscle mass

  1. Leg Muscle Mass and Foot Symptoms, Structure, and Function: The Johnston County Osteoarthritis Project.

    Science.gov (United States)

    Golightly, Yvonne M; Dufour, Alyssa B; Hannan, Marian T; Hillstrom, Howard J; Katz, Patricia P; Jordan, Joanne M

    2016-03-01

    Loss of muscle mass occurs with aging and in lower limbs it may be accelerated by foot problems. In this cross-sectional analysis, we evaluated the relationship of leg muscle mass to foot symptoms (presence or absence of pain, aching, or stiffness), structure while standing (high arch or low arch), and function while walking (pronated or supinated) in a community-based study of Caucasian and African American men and women who were 50-95 years old. In the Johnston County Osteoarthritis Project, leg muscle mass was measured with whole body dual-energy x-ray absorptiometry, and plantar foot pressure data, using predetermined values, were used to classify foot structure and function. Sex-specific crude and adjusted (age, body mass index, and race) linear regression models examined associations of leg muscle mass index (Leg muscle mass [kg]/Height [m](2)) with foot symptoms, structure, and function. Complete data were available for 1,037 participants (mean age 68 years, mean body mass index 31 kg/m(2), 68% women, 29% African American). In women, pronated foot function was associated with lower leg muscle mass in crude (p = .02), but not adjusted (p = .22), models. A low arch was associated with a higher leg muscle mass in adjusted models for both men and women (p Leg muscle mass was associated with foot structure in our biracial sample, whereas relations between leg muscle mass and foot function were attenuated by age, body mass index, and race. Future longitudinal analyses are needed to explain the temporal relationship between these conditions and how they relate to other aspects of impairment and physical function. © The Author 2015. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Leg muscle activation patterns during walking and leg lean mass are different in children with and without developmental coordination disorder.

    Science.gov (United States)

    Yam, Timothy T T; Fong, Shirley S M

    2018-02-01

    Previous studies have shown that children with developmental coordination disorder (DCD) have a higher body fat and greater gait variability. Little research has investigated the gait muscle activity and lean mass measures in children with DCD. To compare the leg muscle activation patterns of the gait cycle and leg lean mass between children with and without DCD. Fifty-one children were in the DCD group (38 males and 13 females; 7.95 ± 1.04 years) and fifty-two in the control group (34 males and 18 females; 8.02 ± 1.00 years). Peak muscle activation patterns of treadmill walking in the right leg for the eight-gait phases were measured by means of surface electromyography, an electrogoniometer, and foot contact switches. Leg lean mass measures were evaluated using a whole-body dual energy X-ray absorptiometry scan. Children with DCD had a lower leg lean mass and appendicular lean mass index compared to the control group. Furthermore, they exhibited a less-pronounced peak muscle activation during the heel strike (gastrocnemius medialis), early swing (biceps femoris) and late swing phases (gastrocnemius medialis) of gait. Although lower limb total mass was similar between groups, the DCD group displayed lower lean mass measures than controls. Furthermore, children with DCD illustrated a lower leg peak muscle activation during the heel strike, early swing and late swing phases of gait when walking on a treadmill. Our results emphasize the need to incorporate lower limb phasic muscle strengthening components into gait rehabilitation programs for children with DCD. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Non-Discriminant Relationships between Leg Muscle Strength, Mass and Gait Performance in Healthy Young and Old Adults

    NARCIS (Netherlands)

    Muehlbauer, Thomas; Granacher, Urs; Borde, Ron; Hortobagyi, Tibor

    2018-01-01

    Background: Gait speed declines with increasing age, but it is unclear if gait speed preferentially correlates with leg muscle strength or mass.  Objective: We determined the relationship between gait speed and (1) leg muscle strength measured at 3 lower extremity joints and (2) leg lean tissue mass

  4. The effectiveness of leucine on muscle protein synthesis, lean body mass and leg lean mass accretion in older people: a systematic review and meta-analysis.

    Science.gov (United States)

    Xu, Zhe-rong; Tan, Zhong-ju; Zhang, Qin; Gui, Qi-feng; Yang, Yun-mei

    2015-01-14

    In the present study, we performed a meta-analysis to assess the ability of leucine supplementation to increase the muscle protein fraction synthetic rate and to augment lean body mass or leg lean mass in elderly patients. A literature search was conducted on Medline, Cochrane, EMBASE and Google Scholar databases up to 31 December 2013 for clinical trials that investigated the administration of leucine as a nutrient that affects muscle protein metabolism and muscle mass in elderly subjects. The included studies were randomised controlled trials. The primary outcome for the meta-analysis was the protein fractional synthetic rate. Secondary outcomes included lean body mass and leg lean mass. A total of nine studies were included in the meta-analysis. The results showed that the muscle protein fractional synthetic rate after intervention significantly increased in the leucine group compared with the control group (pooled standardised difference in mean changes 1·08, 95% CI 0·50, 1·67; Pmass (pooled standardised difference in mean changes 0·18, 95% CI - 0·18, 0·54; P= 0·318) or leg lean mass (pooled standardised difference in mean changes 0·006, 95% CI - 0·32, 0·44; P= 0·756). These findings suggest that leucine supplementation is useful to address the age-related decline in muscle mass in elderly individuals, as it increases the muscle protein fractional synthetic rate.

  5. Leg muscle mass and composition in relation to lower extremity performance in men and women aged 70 to 79 : the health, aging and body composition study

    NARCIS (Netherlands)

    Visser, Marjolein; Kritchevsky, Stephen B; Goodpaster, Bret H; Newman, Anne B; Nevitt, Michael; Stamm, Elizabeth; Harris, Tamara B

    OBJECTIVES: The loss of muscle mass with aging, or sarcopenia, is hypothesized to be associated with the deterioration of physical function. Our aim was to determine whether low leg muscle mass and greater fat infiltration in the muscle were associated with poor lower extremity performance (LEP).

  6. Leg blood flow is impaired during small muscle mass exercise in patients with COPD

    DEFF Research Database (Denmark)

    Iepsen, Ulrik Winning; Munch, Gregers Druedal Wibe; Rugbjerg, Mette

    2017-01-01

    -extensor exercise, and during arterial infusions of sodium nitroprusside (SNP) and acetylcholine (ACh), respectively. Ten patients with moderate to severe COPD and eight age- and sex matched healthy controls were studied. During knee-extensor exercise (10 W), leg blood flow was lower in the patients compared...... the formation of interstitial prostacyclin (vasodilator) was only increased in the controls. There was no difference between groups in the nitrite/nitrate levels (vasodilator) in plasma or interstitial fluid during exercise. Moreover, patients and controls showed similar vasodilatory capacity in response...

  7. LEGS AND TRUNK MUSCLE HYPERTROPHY FOLLOWING WALK TRAINING WITH RESTRICTED LEG MUSCLE BLOOD FLOW

    Directory of Open Access Journals (Sweden)

    Mikako Sakamaki

    2011-06-01

    Full Text Available We examined the effect of walk training combined with blood flow restriction (BFR on the size of blood flow-restricted distal muscles, as well as, on the size of non-restricted muscles in the proximal limb and trunk. Nine men performed walk training with BFR and 8 men performed walk training alone. Training was conducted two times a day, 6 days/wk, for 3 wk using five sets of 2-min bouts (treadmill speed at 50 m/min, with a 1-min rest between bouts. After walk training with BFR, MRI-measured upper (3.8%, P < 0.05 and lower leg (3.2%, P < 0. 05 muscle volume increased significantly, whereas the muscle volume of the gluteus maximus (-0.6% and iliopsoas (1.8% and the muscle CSA of the lumber L4-L5 (-1.0 did not change. There was no significant change in muscle volume in the walk training alone. Our results suggest that the combination of leg muscle blood flow restriction with slow walk training elicits hypertrophy only in the distal blood flow restricted leg muscles. Exercise intensity may be too low during BFR walk training to increase muscle mass in the non- blood flow restricted muscles (gluteus maximus and other trunk muscles.

  8. Twelve weeks’ progressive resistance training combined with protein supplementation beyond habitual intakes increases upper leg lean tissue mass, muscle strength and extended gait speed in healthy older women.

    OpenAIRE

    Francis, P

    2016-01-01

    The age-related decline in functional capability is preceded by a reduction in muscle quality. The purpose of this study was to assess the combined effects of progressive resistance training (PRT) and protein supplementation beyond habitual intakes on upper leg lean tissue mass (LTM), muscle quality and functional capability in healthy 50 – 70y women. In a single-blinded, randomized, controlled design, 57 healthy older women (age 61.1 ± 5.1 years, 1.61 ± 0.65 m, 65.3 ± 15.3 kg) consumed 0.33 ...

  9. Block-step asymmetry 5 years after large-head metal-on-metal total hip arthroplasty is related to lower muscle mass and leg power on the implant side.

    Science.gov (United States)

    Hjorth, M H; Stilling, M; Lorenzen, N D; Jakobsen, S S; Soballe, K; Mechlenburg, I

    2014-06-01

    Metal-on-metal articulations mimic the human hip anatomy, presumably lower dislocation rates and increase the range-of-motion. This study aims to measure the muscle mass and power of both legs in patients with unilateral metal-on-metal total hip arthroplasty, and to investigate their effect on block-step test, spatio-temporal gait parameters and self-reported function. Twenty-eight patients (7 women), mean age 50 (28-68) years, participated in a 5-7 year follow-up. Patients had received one type unilateral large-head metal-on-metal total hip articulation, all of which were well-functioning at follow-up. Mean muscle mass was measured by the total-body Dual energy X-ray Absorption scans, and muscle power was measured in a leg extensor power rig. Block-step test and spatio-temporal gait parameters were measured with an inertial measurement unit. Self-reported function was assessed by the Hip Disability and Osteoarthritis Outcome Score. We found a significant difference between the mean muscle mass of the implant-side leg and the non-implant-side leg in hip, thigh and calf areas (Ppower (P=0.025). Correlations between mean muscle mass and mean muscle power were significant for both the implant-side leg (r=0.45, P=0.018) and the non-implant-side leg (r=0.51, P=0.007). The difference in mean muscle power between legs correlated with block-step test asymmetry during ascending (r=0.40, P=0.047) and descending (r=0.53, P=0.006). Correlations between self-reported function and power of the implant-side leg were not significant. Young patients have not fully regained muscle mass, muscle power and function 5-7 years after metal-on-metal total hip arthroplasty. Copyright © 2014. Published by Elsevier Ltd.

  10. A low arm and leg muscle mass to total body weight ratio is associated with an increased prevalence of metabolic syndrome: The Korea National Health and Nutrition Examination Survey 2010-2011.

    Science.gov (United States)

    Kim, Yong Hwan; So, Wi-Young

    2016-09-14

    The aim of this study was to investigate the association between metabolic syndrome (MetS) and arm and leg muscle mass to total weight ratios in Korean adults. This was a randomized, controlled, cross-sectional study. Data from 2,383 adults (1,030 men and 1,353 women) were collected from the Korea National Health and Nutrition Examination Survey 2010-2011. Blood lipid profiles, blood pressure, and anthropometric characteristics, including weight, height, waist circumference, and muscle mass on dual energy X-ray absorptiometry (DXA), were evaluated in the participants. MetS was defined according to the criteria of the National Cholesterol Education Program Adult Treatment Panel III. The average mass of both arms and legs was determined using regional muscle analysis by DXA. Afterwards, the arm and leg muscle mass to total body weight ratio was determined and classified into 4 quartiles (i.e., quartile 1 [highest muscle ratio] to quartile 4 [lowest muscle ratio]). According to the arm muscle and leg muscle ratios, there was a higher prevalence of MetS in quartile 4 than in quartile 1 in both men and women. A low arm and leg muscle mass to body weight ratio was associated with a higher prevalence of MetS after adjusting for age, physical activity, frequency of smoking, and frequency of alcohol consumption. In conclusion, MetS patients demonstrated a lower arm and leg muscle mass to body weight ratio. Strength training for the lower and upper extremities is recommended because it can have a positive effect on MetS prevention.

  11. Six weeks' aerobic retraining after two weeks' immobilization restores leg lean mass and aerobic capacity but does not fully rehabilitate leg strenght in young and older men

    DEFF Research Database (Denmark)

    Vigelsø Hansen, Andreas; Gram, Martin; Wiuff, Caroline

    2015-01-01

    OBJECTIVE: To determine the effect of aerobic retraining as rehabilitation after short-term leg immobilization on leg strength, leg work capacity, leg lean mass, leg muscle fibre type composition and leg capillary supply, in young and older men. SUBJECTS AND DESIGN: Seventeen young (23 ± 1 years...... immobilization had marked effects on leg strength, and work capacity and 6 weeks' retraining was sufficient to increase, but not completely rehabilitate, muscle strength, and to rehabilitate aerobic work capacity and leg lean mass (in the young men)....

  12. Twelve weeks' progressive resistance training combined with protein supplementation beyond habitual intakes increases upper leg lean tissue mass, muscle strength and extended gait speed in healthy older women.

    Science.gov (United States)

    Francis, Peter; Mc Cormack, William; Toomey, Clodagh; Norton, Catherine; Saunders, Jean; Kerin, Emmet; Lyons, Mark; Jakeman, Philip

    2017-12-01

    The age-related decline in functional capability is preceded by a reduction in muscle quality. The purpose of this study was to assess the combined effects of progressive resistance training (PRT) and protein supplementation beyond habitual intakes on upper leg lean tissue mass (LTM), muscle quality and functional capability in healthy 50-70 years women. In a single-blinded, randomized, controlled design, 57 healthy older women (age 61.1 ± 5.1 years, 1.61 ± 0.65 m, 65.3 ± 15.3 kg) consumed 0.33 g/kg body mass of a milk-based protein matrix (PRO) for 12 weeks. Of the 57 women, 29 also engaged in a PRT intervention (PRO + PRT). In comparison to the PRO group (n = 28), those in the PRO + PRT group had an increase in upper leg LTM [0.04 (95% CI -0.07 to 0.01) kg vs. 0.13 (95% CI 0.08-0.18) kg, P = 0.027], as measured by Dual-energy X-ray absorptiometry; an increase in knee extensor (KE) torque [-1.6 (95% CI -7.3 to 4.4 N m) vs. 10.2 (95% CI 4.3-15.8 N m), P = 0.007], as measured from a maximal voluntary isometric contraction (Con-Trex MJ; CMV AG); and an increase in extended gait speed [-0.01 (95% CI -0.52-0.04) m s -1 vs. 0.10 (95% CI 0.05-0.22) m s -1 , P = 0.001] as measured from a maximal 900 m effort. There was no difference between groups in the time taken to complete 5 chair rises or the number of chair rises performed in 30 s (P > 0.05). PRT in healthy older women ingesting a dietary protein supplement is an effective strategy to improve upper leg LTM, KE torque and extended gait speed in healthy older women.

  13. Association between Thigh Muscle Volume and Leg Muscle Power in Older Women.

    Directory of Open Access Journals (Sweden)

    Ulrich Lindemann

    Full Text Available The construct of sarcopenia is still discussed with regard to best appropriate measures of muscle volume and muscle function. The aim of this post-hoc analysis of a cross-sectional experimental study was to investigate and describe the hierarchy of the association between thigh muscle volume and measurements of functional performance in older women. Thigh muscle volume of 68 independently living older women (mean age 77.6 years was measured via magnetic resonance imaging. Isometric strength was assessed for leg extension in a movement laboratory in sitting position with the knee flexed at 90° and for hand grip. Maximum and habitual gait speed was measured on an electronic walk way. Leg muscle power was measured during single leg push and during sit-to-stand performance. Thigh muscle volume was associated with sit-to-stand performance power (r = 0.628, leg push power (r = 0.550, isometric quadriceps strength (r = 0.442, hand grip strength (r = 0.367, fast gait speed (r = 0.291, habitual gait speed (r = 0.256, body mass index (r = 0.411 and age (r = -0.392. Muscle power showed the highest association with thigh muscle volume in healthy older women. Sit-to-stand performance power showed an even higher association with thigh muscle volume compared to single leg push power.

  14. Reconstruction of human swing leg motion with passive biarticular muscle models.

    Science.gov (United States)

    Ahmad Sharbafi, Maziar; Mohammadi Nejad Rashty, Aida; Rode, Christian; Seyfarth, Andre

    2017-04-01

    Template models, which are utilized to demonstrate general aspects in human locomotion, mostly investigate stance leg operation. The goal of this paper is presenting a new conceptual walking model benefiting from swing leg dynamics. Considering a double pendulum equipped with combinations of biarticular springs for the swing leg beside spring-mass (SLIP) model for the stance leg, a novel SLIP-based model, is proposed to explain human-like leg behavior in walking. The action of biarticular muscles in swing leg motion helps represent human walking features, like leg retraction, ground reaction force and generating symmetric walking patterns, in simulations. In order to stabilize the motion by the proposed passive structure, swing leg biarticular muscle parameters such as lever arm ratios, stiffnesses and rest lengths need to be properly adjusted. Comparison of simulation results with human experiments shows the ability of the proposed model in replicating kinematic and kinetic behavior of both stance and swing legs as well as biarticular thigh muscle force of the swing leg. This substantiates the important functional role of biarticular muscles in leg swing. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Possibility of leg muscle hypertrophy by ambulation in older adults: a brief review

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    Ozaki H

    2013-03-01

    Full Text Available Hayao Ozaki,1 Jeremy P Loenneke,2 Robert S Thiebaud,2 Joel M Stager,3 Takashi Abe31Juntendo University, Inzai, Chiba, Japan; 2Department of Health and Exercise Science, University of Oklahoma, Norman, OK, USA; 3Department of Kinesiology, Indiana University, Bloomington, IN, USAAbstract: It is known that ambulatory exercises such as brisk walking and jogging are potent stimuli for improving aerobic capacity, but it is less understood whether ambulatory exercise can increase leg muscle size and function. The purpose of this brief review is to discuss whether or not ambulatory exercise elicits leg muscle hypertrophy in older adults. Daily ambulatory activity with moderate (>3 metabolic equivalents [METs], which is defined as the ratio of the work metabolic rate to the resting metabolic rate intensity estimated by accelerometer is positively correlated with lower body muscle size and function in older adults. Although there is conflicting data on the effects of short-term training, it is possible that relatively long periods of walking, jogging, or intermittent running for over half a year can increase leg muscle size among older adults. In addition, slow-walk training with a combination of leg muscle blood flow restriction elicits muscle hypertrophy only in the blood flow restricted leg muscles. Competitive marathon running and regular high intensity distance running in young and middle-aged adults may not produce leg muscle hypertrophy due to insufficient recovery from the damaging running bout, although there have been no studies that have investigated the effects of running on leg muscle morphology in older subjects. It is clear that skeletal muscle hypertrophy can occur independently of exercise mode and load.Keywords: aerobic exercise, muscle mass, aging, strength, sarcopenia

  16. Effect of transcutaneous electrical muscle stimulation on postoperative muscle mass and protein synthesis

    DEFF Research Database (Denmark)

    Vinge, O; Edvardsen, L; Jensen, F

    1996-01-01

    In an experimental study, 13 patients undergoing major elective abdominal surgery were given postoperative transcutaneous electrical muscle stimulation (TEMS) to the quadriceps femoris muscle on one leg; the opposite leg served as control. Changes in cross-sectional area (CSA) and muscle protein ...... muscle protein synthesis and muscle mass after abdominal surgery and should be evaluated in other catabolic states with muscle wasting.......In an experimental study, 13 patients undergoing major elective abdominal surgery were given postoperative transcutaneous electrical muscle stimulation (TEMS) to the quadriceps femoris muscle on one leg; the opposite leg served as control. Changes in cross-sectional area (CSA) and muscle protein...... synthesis were assessed by computed tomography and ribosome analysis of percutaneous muscle biopsies before surgery and on the sixth postoperative day. The percentage of polyribosomes in the ribosome suspension decreased significantly (P

  17. Differential catabolism of muscle protein in garden warblers (Sylvia borin): flight and leg muscle act as a protein source during long-distance migration.

    Science.gov (United States)

    Bauchinger, U; Biebach, H

    2001-05-01

    Samples of flight and leg muscle tissue were taken from migratory garden warblers at three different stages of migration: (1) pre-flight: when birds face an extended flight phase within the next few days, (2) post-flight: when they have just completed an extended flight phase, and (3) recovery: when they are at the end of a stop-over period following an extended flight phase. The changes in body mass are closely related to the changes in flight (Pflight. From pre- to post-flight, the flight and the leg muscle masses decrease by about 22%, but are restored to about 12% above the pre-flight masses during the recovery period. Biochemical analyses show that following flight a selective reduction occurred in the myofibrillar (contractile) component of the flight muscle (Pflight and leg muscle act as a protein source during long-distance migration. As a loss of leg muscle mass is additionally observed besides the loss in flight muscle mass, mass change seems not to be strictly associated with the mechanical power output requirements during flight. Whereas the specific content of sarcoplasmic proteins in the flight muscle is nearly twice as high as that in the leg muscle (Pflight muscle is one of the highest observed in muscles of a vertebrate.

  18. Muscle hernias of the lower leg: MRI findings

    Energy Technology Data Exchange (ETDEWEB)

    Mellado, J.M. [Radiology Department, Hospital Virgen de la Cinta, Tortosa, Tarragona (Spain)]|[IDI - Centre Tarragona, Ressonancia Magnetica, Hospital Joan XXIII, Tarragona (Spain); Perez del Palomar, L. [Radiology Department, Hospital Virgen de la Cinta, Tortosa, Tarragona (Spain)

    1999-08-01

    Muscle hernias of the lower leg involving the tibialis anterior, peroneus brevis, and lateral head of the gastrocnemius were found in three different patients. MRI findings allowed recognition of herniated muscle in all cases and identification of fascial defect in two of them. MR imaging findings and the value of dynamic MR imaging is emphasized. (orig.) With 3 figs., 10 refs.

  19. Leg muscle power in 12-year-old black and white Tunisian football players.

    Science.gov (United States)

    Ben Ayed, Karim; Latiri, Imed; Dore, Eric; Tabka, Zouhair

    2011-04-01

    This study examined leg muscle power of young male Tunisian black and white football players and extended the analysis to determine whether there is a relationship between cycling peak power output (PPO) and some field tests. A total of 113 children (white group (WG) = n = 56; black group (BG) = n = 57) participated in this investigation. Anthropometric data included age, body mass (BM), height, leg length (LL), body mass index (BMI), and leg muscle volume (LMV). Cycling PPO was measured including a force-velocity test. Peak power output (PPO; W and W/kg), Fopt (optimal braking force), and Vopt (optimal velocity) were significantly higher in the WG compared with the BG (p force-velocity test as explanatory factors showed that 33% of the variance of PPO of BG was explained by qualitative factors that may be related to cycling skill, muscle composition, and socioeconomic and training status.

  20. Interaction Between Leg Muscle Performance and Sprint Acceleration Kinematics

    Directory of Open Access Journals (Sweden)

    Lockie Robert G.

    2015-12-01

    Full Text Available This study investigated relationships between 10 m sprint acceleration, step kinematics (step length and frequency, contact and flight time, and leg muscle performance (power, stiffness, strength. Twenty-eight field sport athletes completed 10 m sprints that were timed and filmed. Velocity and step kinematics were measured for the 0-5, 5-10, and 0-10 m intervals to assess acceleration. Leg power was measured via countermovement jumps (CMJ, a fivebound test (5BT, and the reactive strength index (RSI defined by 40 cm drop jumps. Leg stiffness was measured by bilateral and unilateral hopping. A three-repetition maximum squat determined strength. Pearson’s correlations and stepwise regression (p ≤ 0.05 determined velocity, step kinematics, and leg muscle performance relationships. CMJ height correlated with and predicted velocity in all intervals (r = 0.40-0.54. The 5BT (5-10 and 0-10 m intervals and RSI (5-10 m interval also related to velocity (r = 0.37-0.47. Leg stiffness did not correlate with acceleration kinematics. Greater leg strength related to and predicted lower 0-5 m flight times (r = -0.46 to -0.51, and a longer 0-10 m step length (r = 0.38. Although results supported research emphasizing the value of leg power and strength for acceleration, the correlations and predictive relationships (r2 = 0.14-0.29 tended to be low, which highlights the complex interaction between sprint technique and leg muscle performance. Nonetheless, given the established relationships between speed, leg power and strength, strength and conditioning coaches should ensure these qualities are expressed during acceleration in field sport athletes.

  1. Interaction Between Leg Muscle Performance and Sprint Acceleration Kinematics.

    Science.gov (United States)

    Lockie, Robert G; Jalilvand, Farzad; Callaghan, Samuel J; Jeffriess, Matthew D; Murphy, Aron J

    2015-12-22

    This study investigated relationships between 10 m sprint acceleration, step kinematics (step length and frequency, contact and flight time), and leg muscle performance (power, stiffness, strength). Twenty-eight field sport athletes completed 10 m sprints that were timed and filmed. Velocity and step kinematics were measured for the 0-5, 5-10, and 0-10 m intervals to assess acceleration. Leg power was measured via countermovement jumps (CMJ), a five-bound test (5BT), and the reactive strength index (RSI) defined by 40 cm drop jumps. Leg stiffness was measured by bilateral and unilateral hopping. A three-repetition maximum squat determined strength. Pearson's correlations and stepwise regression (p ≤ 0.05) determined velocity, step kinematics, and leg muscle performance relationships. CMJ height correlated with and predicted velocity in all intervals (r = 0.40-0.54). The 5BT (5-10 and 0-10 m intervals) and RSI (5-10 m interval) also related to velocity (r = 0.37-0.47). Leg stiffness did not correlate with acceleration kinematics. Greater leg strength related to and predicted lower 0-5 m flight times (r = -0.46 to -0.51), and a longer 0-10 m step length (r = 0.38). Although results supported research emphasizing the value of leg power and strength for acceleration, the correlations and predictive relationships (r(2) = 0.14-0.29) tended to be low, which highlights the complex interaction between sprint technique and leg muscle performance. Nonetheless, given the established relationships between speed, leg power and strength, strength and conditioning coaches should ensure these qualities are expressed during acceleration in field sport athletes.

  2. Muscle strategies for leg extensions on a "Reformer" apparatus.

    Science.gov (United States)

    Cantergi, Débora; Loss, Jefferson Fagundes; Jinha, Azim; Brodt, Guilherme Auler; Herzog, Walter

    2015-04-01

    Considering the kinematics of leg extensions performed on a Reformer apparatus, one would expect high activation of hip and knee extensor muscle groups. However, because of the bi-articular nature of some lower limb muscles, and the possibility to vary the direction of force application on the Reformer bar, muscles can be coordinated theoretically in a variety of ways and still achieve the desired outcome. Hence, the aim of this study was to determine the knee and hip moments during leg extensions performed on the Reformer apparatus and to estimate the forces in individual muscles crossing these joints using static optimization. Fifteen subjects performed leg extensions exercises on the Reformer apparatus using an individually chosen resistance. To our big surprise, we found that subjects performed the exercise using two conceptually different strategies (i) the first group used simultaneous hip and knee extension moments, (ii) while the second group used simultaneous hip flexion and knee extension moments to perform the exercise. These different strategies were achieved by changing the direction of the resultant force applied by the subject's feet on the Reformer bar. While leg extensions on the Reformer apparatus have been thought to strengthen the hip and knee extensors muscles, our results demonstrate that patients can perform the exercise in a different and unexpected way. In order to control the hip and knee moments and achieve the desired outcome of the exercise, the direction of force application on the Reformer bar must be controlled carefully. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Interleukin-6 release is higher across arm than leg muscles during whole-body exercise

    DEFF Research Database (Denmark)

    Helge, Jørn W; Klein, Ditte K; Andersen, Thor Munch

    2011-01-01

    ± 7 and 47 ± 7 µmol min(-1) (kg lean limb mass)(-1)) were lower, glucose uptake similar (51 ± 12 and 41 ± 8 mmol min(-1) (kg lean limb mass)(-1)) and lactate release higher (82 ± 32 and -2 ± 12 µmol min(-1) (kg lean limb mass)(-1)) in arms than legs, respectively, during exercise (P ....05). No correlations were present between IL-6 release and exogenous substrate uptakes. Muscle glycogen was similar in arms and legs before exercise (388 ± 22 and 428 ± 25 mmol (kg dry weight)(-1)), but after exercise it was only significantly lower in the leg (219 ± 29 mmol (kg dry weight)(-1)). The novel finding......Exercising muscle releases interleukin-6 (IL-6), but the mechanisms controlling this process are poorly understood. This study was performed to test the hypothesis that the IL-6 release differs in arm and leg muscle during whole-body exercise, owing to differences in muscle metabolism. Sixteen...

  4. Work economy following strength training in elderly : alterations in muscle strength, muscle thickness and lean mass upon work economy in elderly men following 12 weeks of strength training

    OpenAIRE

    Salvesen, Svein

    2013-01-01

    Masteroppgave i idrettsvitenskap - Universitetet i Agder 2013 AIM: To investigate if alterations in muscle strength, muscle mass and muscle thickness were followed by changes in work economy. METHODS: Fifty elderly men (60 – 81 years) followed a 12 week undulating periodized strength training program: Lean mass (Muscle mass; Dual-energy X-ray absorptiometry), muscle strength (1RM; one repetition maximum, in leg press and leg extension), and muscle thickness (ultrasound; vastus lateralis a...

  5. Does EMG activation differ among fatigue-resistant leg muscles ...

    African Journals Online (AJOL)

    The participants (N=32) were divided into two groups according to the Fatigue Index value [Group I: Less Fatigue Resistant (LFR), n=17; Group II: More Fatigue Resistant (MFR), n=15]. The repeated EMG activities of four leg muscles [rectus femoris, biceps femoris, vastus lateralis and vastus medialis] were analysed during ...

  6. Muscle recruitment patterns during the prone leg extension

    Directory of Open Access Journals (Sweden)

    Rayfield Ben

    2004-02-01

    Full Text Available Abstract Background The prone leg extension (PLE is a clinical test used to evaluate the function of the lumbopelvis. It has been theorized that a normal and consistent pattern of muscle activation exists. Previous research has found two contradictory patterns of muscle activation during PLE in normal individuals. One study shows an almost simultaneous activation of the lower erector spinae and hamstring muscle group with a delayed activation of the gluteus maximus, while the second describes the order of activation being ipsilateral erector spinae (to the leg being extended, hamstrings, contralateral erector spinae and gluteus maximus. Due to the different conclusions from these two studies and the lack of quantified muscle onset times, expressed in absolute time this study attempted to quantify the muscle onset times (in milliseconds during the prone leg extension, while noting if a consistent order of activation exists and whether a timing relationship also exists between the gluteus maximus and contralateral latissimus dorsi. Methods 10 asymptomatic males (Average height: 175.2 cm (SD 6.5, Average Weight 75.9 kg (SD 6.5, Average Age: 27.1(SD 1.28 and 4 asymptomatic females (Average height 164.5 (SD 2.9, weight: 56.2 (SD 8.9, Average Age: 25 (SD 1 performed the prone leg extension task while the myoelectric signal was recorded from the bilateral lower erector spinae, gluteus maximus and hamstring muscle groups. Activation onsets were determined from the rectified EMG signal relative to the onset of the hamstrings muscle group. Results No consistent recruitment patterns were detected for prone leg extension among the hamstring muscle group and the erector spinae. However, a consistent delay in the Gluteus Maximus firing of approximately 370 ms after the first muscle activated was found. Five out of 14 asymptomatic subjects showed a delay in gluteus maximus firing exceeding the average delay found in previous research of subjects considered to

  7. Muscle activity of leg muscles during unipedal stance on therapy devices with different stability properties.

    Science.gov (United States)

    Wolburg, Thomas; Rapp, Walter; Rieger, Jochen; Horstmann, Thomas

    2016-01-01

    To test the hypotheses that less stable therapy devices require greater muscle activity and that lower leg muscles will have greater increases in muscle activity with less stable therapy devices than upper leg muscles. Cross-sectional laboratory study. Laboratory setting. Twenty-five healthy subjects. Electromyographic activity of four lower (gastrocnemius medialis, soleus, tibialis anterior, peroneus longus) and four upper leg muscles (vastus medialis and lateralis, biceps femoris, semitendinosus) during unipedal quiet barefoot stance on the dominant leg on a flat rigid surface and on five therapy devices with varying stability properties. Muscle activity during unipedal stance differed significantly between therapy devices (P leg) and therapy device (P = 0.985). Magnitudes of additional relative muscle activity for the respective therapy devices differed substantially among lower extremity muscles. The therapy devices offer a progressive increase in training intensity, and thus may be useful for incremental training programs in physiotherapeutic practice and sports training programs. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Analysis of the body mass index and leg profiles of Asian women after total leg sculpture.

    Science.gov (United States)

    Tsai, Feng-Chou; Chen, Chien-Hao; Lin, Chan-Yi; Ho, Li-Yung

    2009-08-01

    In addition to the conventional methods used to improve leg contours, total leg sculpture, including liposuction, selective neurectomy, and transilluminated powered phlebectomy, provides a one-time solution of leg contour problems, which is a major aesthetic concern among Asian women. The authors present the postoperative results of total leg sculpture and determine any significance and correlation between the leg variables and body mass index by statistical analysis. Thirty female patients who underwent total leg sculpture between 2005 and 2008 were included in the study, and prospective analysis of the patients' data was performed during a follow-up period of 1 year. Local measurement variables and body mass index were recorded, and the correlation between them was determined by Pearson's correlation and regression analysis. A paired t test was used to compare the postoperative outcomes. Subjectively, all patient results were satisfactory. There were significant differences between preoperative and postoperative measurements for all variables for total leg sculpture. Body mass index was strongly correlated with all leg indexes, and there was a significant positive correlation between the index and variables related to the buttocks and upper thigh. The satisfactory postoperative leg variables were buttocks circumference (87.85 cm), thigh circumference (T60, 44.20 cm), maximal calf circumference (32.24 cm), and calf ratio (0.78). Each preoperative body mass index increment represents a 0.3 percent circumference improvement around the buttocks after surgery. No obvious morbidities or long-term hospital stays were noted. Total leg sculpture provides a combined aesthetic solution for improving limb contours with minimal morbidity. Patients with larger body mass index values exhibit better aesthetic improvement than those with smaller values.

  9. Use of local muscle flaps to cover leg bone exposures

    Directory of Open Access Journals (Sweden)

    Francisco d'Avila

    Full Text Available Objective: To evaluate the use of the medial gastrocnemius muscle and/or soleus muscle flaps as surgical treatment of the leg bone exposure.Methods: We retrospectively analyzed the medical records of patients undergoing transposition of the medial gastrocnemius and / or soleus for treating exposed bone in the leg, from January 1976 to July 2009, gathering information on epidemiological data, the etiology the lesion, the time between the initial injury and muscle transposition, the muscle used to cover the lesion, the healing evolution of the skin coverage and the function of the gastrocnemius-soleus unit.Results: 53 patients were operated, the ages varying between nine and 84 years (mean age 41; 42 were male and 11 female. The main initial injury was trauma (84.8%, consisting of tibia and / or fibula fracture. The most frequently used muscle was the soleus, in 40 cases (75.5%. The rank of 49 patients (92.5% was excellent or good outcome, of three (5.6% as regular and of one (1.9% as unsatisfactory.Conclusion: the treatment of bone exposure with local muscle flaps (gastrocnemius and/or soleus enables obtaining satisfactory results in covering of exposed structures, favoring local vascularization and improving the initial injury. It offers the advantage of providing a treatment in only one surgical procedure, an earlier recovery and reduced hospital stay.

  10. Norepinephrine spillover from skeletal muscle during exercise in humans: role of muscle mass.

    Science.gov (United States)

    Savard, G K; Richter, E A; Strange, S; Kiens, B; Christensen, N J; Saltin, B

    1989-12-01

    The purpose of this study was to determine the effect of increasing muscle mass involvement in dynamic exercise on both sympathetic nervous activation and local hemodynamic variables of individual active and inactive skeletal muscle groups. Six male subjects performed 15-min bouts of one-legged knee extension either alone or in combination with the knee extensors of the other leg and/or with the arms. The range of work intensities varied between 24 and 71% (mean) of subjects' maximal aerobic capacity (% VO2max). Leg blood flow, measured in the femoral vein by thermodilution, was determined in both legs. Arterial and venous plasma concentrations of norepinephrine (NE) and epinephrine were analyzed, and the calculated NE spillover was used as an index of sympathetic nervous activity to the limb. NE spillover increased gradually both in the resting, and to a larger extent in the exercising legs, with a steeper rise occurring approximately 70% VO2max. These increases were not associated with any significant changes in leg blood flow or leg vascular conductance at the exercise intensities examined. These results suggest that, as the total active muscle mass increases, the rise in sympathetic nervous activity to skeletal muscle, either resting or working at a constant load, is not associated with any significant neurogenic vasoconstriction and reduction in flow or conductance through the muscle vascular bed, during whole body exercise demanding up to 71% VO2max.

  11. Differential glucose uptake in quadriceps and other leg muscles during one-legged dynamic submaximal knee-extension exercise

    Directory of Open Access Journals (Sweden)

    Kari eKalliokoski

    2011-10-01

    Full Text Available One-legged dynamic knee-extension exercise (DKE is a widely used model to study the local cardiovascular and metabolic responses to exercise of the quadriceps muscles. In this study, we explored the extent to which different muscles of the quadriceps are activated during exercise using positron emission tomography (PET determined uptake of [18F]-fluoro-deoxy-glucose (GU during DKE. Five healthy male subjects performed DKE at 25 W for 35 min and both the contracting and contralateral resting leg were scanned with PET from mid-thigh and distally. On average, exercise GU was the highest in the vastus intermedius (VI and lowest in the vastus lateralis (VL (VI vs VL, p<0.05, whereas the coefficient of variation was highest in VL (VL vs VI, p<0.05. Coefficient of variation between the mean values of the four QF muscles in the exercising leg was 35±9%. Compared to mean GU in QF (=100%, GU was on average 73% in VL, 84% in rectus femoris, 115% in vastus medialis, and 142% in VI. Variable activation of hamstring muscles and muscles of the lower leg was also observed. These results show that GU of different muscles of quadriceps muscle group as well as between individuals vary greatly during DKE, and suggests that muscle activity is not equal between quadriceps muscles in this exercise model. Furthermore, posterior thigh muscles and lower leg muscles are more active than hitherto thought even during this moderate exercise intensity.

  12. The Comparing the Leg Muscles Electromyography during Single Leg Drop Landing in Pesplanus and Normal Men

    Directory of Open Access Journals (Sweden)

    mostafa bazvand

    2016-03-01

    Full Text Available Objective: pesplanus is one of the changes that brings about changes in muscle activation patterns. Being aware of muscles activity changes in various standing positions among pesplanus patients provides insights into preventing lower extremity injuries in this population. The aim of this study was to compare leg muscles electromyography during various standing positions in pesplanus and normal subjects. Methods: 60 healthy male university students, 30 subjects with pesplanus deformity (with average age 23/54±3/57 year, average height 175/34±7/62 cm, average weight 74/87±10/72 kg and 30 normal subjects (with average age 22/97±2/38 year, average height 176/6±5/59 cm, average weight 73/58±8/36 kg participated in this comparative study. Deformity of pesplanus was assessed with navicular drop test. Each subject performed single-leg landing dropping from 30cm height onto a force platform where muscles activity was recorded with EMG device. For data analysis, Matlab and Spss softwares were used and independent sample t-test was used to compare the dependent variables at a significance level of P &le 0/05. Results: Significant differences were observed between the two groups for the activities of the longus peroneus and anterior tibialis muscles ( p&le0/05 while no significant differences were observed in other muscles. Conclusion: The changes in the normal structure of the foot might affect muscle activities during standing, which can cause changes in the injury patterns. Therefore, it is proposed that focusing on corrective exercises and therapy plan can reduce these risks.

  13. Elicitability of muscle cramps in different leg and foot muscles.

    Science.gov (United States)

    Minetto, Marco Alessandro; Botter, Alberto

    2009-10-01

    To explore the efficacy of muscle motor point stimulation in eliciting muscle cramps, 11 subjects underwent eight sessions of electrical stimulation of the following muscles bilaterally: abductor hallucis flexor hallucis brevis, and both heads of the gastrocnemius muscles. Bursts of 150 square wave stimuli (duration: 152 micros; current intensity: 30% supramaximal) were applied. The stimulation frequency was increased from 4 pulses per second (pps) at increments of 2 pps until a cramp was induced. The number of cramps that could be elicited was smaller in flexor hallucis brevis than in abductor hallucis (16 vs. 22 out of 22 trials each; P cramp susceptibility, and the intermuscle variability in the elicitability profile for electrically induced cramps supports the use of the proposed method for cramp research.

  14. Differential glucose uptake in quadriceps and other leg muscles during one-legged dynamic submaximal knee-extension exercise

    DEFF Research Database (Denmark)

    Kalliokoski, Kari K; Boushel, Robert; Langberg, Henning

    2011-01-01

    to mean GU in QF (=100%), GU was on average 73% in VL, 84% in rectus femoris, 115% in vastus medialis, and 142% in VI. Variable activation of hamstring muscles and muscles of the lower leg was also observed. These results show that GU of different muscles of quadriceps muscle group as well as between......One-legged dynamic knee-extension exercise (DKE) is a widely used model to study the local cardiovascular and metabolic responses to exercise of the quadriceps muscles. In this study, we explored the extent to which different muscles of the quadriceps are activated during exercise using positron...... in the vastus intermedius (VI) and lowest in the vastus lateralis (VL; VI vs VL, p muscles in the exercising leg was 35 ± 9%. Compared...

  15. The effects of anthropometry and leg muscle power on drive and transition phase of acceleration

    DEFF Research Database (Denmark)

    Nikolaidis, Pantelis T.; Ingebrigtsen, Jørgen; Jeffreys, Ian

    2016-01-01

    Background: The aim of this study was to examine the effect of anthropometry and leg muscle power on accelerative ability and its phases (drive and transition). METHODS: Thirty-six soccer players (age 12.4±1.2 years, body mass 49.9±8.9 kg and height 154.2±10.3 cm) were tested twice, in the beginn...

  16. THE EFFECTS OF SINGLE LEG HOP PROGRESSION AND DOUBLE LEGS HOP PROGRESSION EXERCISE TO INCREASE SPEED AND EXPLOSIVE POWER OF LEG MUSCLE

    Directory of Open Access Journals (Sweden)

    Nining W. Kusnanik

    2015-05-01

    Full Text Available The main purpose of this study was to determine the effect of single leg hop progression and double legs hop progression exercise to increase speed and explosive power of leg muscles. Plyometric is one of the training methods that can increase explosive power. There are many models of plyometric training including single leg hop progression and double leg hop progression. This research was experimental using match subject design techniques. The subjects of this study were 39 students who joined basketball school club. There were 3 groups in this study: Group 1 were 13 students who given sin¬gle leg hop progression exercise, Group 2 were 13 students who given double legs hop progression exercise, Group 3 were 13 students who given conventional exercise. The data was collected during pre test and post test by testing 30m speed running and vertical jump. The data was analyzed using Analysis of Varians (Anova. It was found that there were significantly increased on speed and explosive power of leg muscles of Group 1 and Group 2. It can be stated that single leg hop progression exercise was more effective than double leg hop progression exercise. The recent findings supported the hypothesis that single leg hop progression and double legs hop progression exercise can increase speed and explosive power of leg muscles. These finding were supported by some previous studies (Singh, et al, 2011; Shallaby, H.K., 2010. The single leg hop progression is more effective than double legs hop progression. This finding was consistent with some previous evidences (McCurdy, et al, 2005; Makaruk et al, 2011.

  17. Motor-neuron pool excitability of the lower leg muscles after acute lateral ankle sprain.

    Science.gov (United States)

    Klykken, Lindsey W; Pietrosimone, Brian G; Kim, Kyung-Min; Ingersoll, Christopher D; Hertel, Jay

    2011-01-01

    Neuromuscular deficits in leg muscles that are associated with arthrogenic muscle inhibition have been reported in people with chronic ankle instability, yet whether these neuromuscular alterations are present in individuals with acute sprains is unknown. To compare the effect of acute lateral ankle sprain on the motor-neuron pool excitability (MNPE) of injured leg muscles with that of uninjured contralateral leg muscles and the leg muscles of healthy controls. Case-control study. Laboratory. Ten individuals with acute ankle sprains (6 females, 4 males; age= 19.2 ± 3.8 years, height= 169.4 ± 8.5 cm, mass= 66.3 ± 11.6 kg) and 10 healthy individuals(6 females,4 males; age= 20.6 ± 4.0 years, height = 169.9 ± 10.6 cm, mass= 66.3 ± 10.2 kg) participated. The independent variables were group (acute ankle sprain, healthy) and limb (injured, uninjured). Separate dependent t tests were used to determine differences in MNPE between legs. The MNPE of the soleus, fibularis longus, and tibialis anterior was measured by the maximal Hoffmann reflex (H(max)) and maximal muscle response (M(max)) and was then normalized using the H(max):M(max) ratio. The soleus MNPE in the ankle-sprain group was higher in the injured limb (H(max):M(max) = 0.63; 95% confidence interval [Cl],0.46, 0.80) than the uninjured limb (H(max):M(max) = 0.47; 95%Cl, 0.08, 0.93)(t(6) = 3.62,P =.01).In the acute ankle-sprain group, tibialis anterior MNPE tended to be lower in the injured ankle (H(max):M(max) =0.06; 95% Cl, 0.01, 0.10) than in the uninjured ankle (H(max):M(max) =0.22; 95%Cl, 0.09, 0.35),but this finding was not different (t(9) =-2.01, P =.07). No differences were detected between injured (0.22; 95% Cl, 0.14, 0.29) and uninjured (0.25; 95%Cl, 0.12, 0.38) ankles for the fibularis longus in the ankle-sprain group (t(9) =-0.739, P =.48). We found no side-to-side differences in any muscle among the healthy group. Facilitated MNPE was present in the involved soleus muscle of patients with acute

  18. Relationship between Leg Mass, Leg Composition and Foot Velocity on Kicking Accuracy in Australian Football.

    Science.gov (United States)

    Hart, Nicolas H; Nimphius, Sophia; Spiteri, Tania; Cochrane, Jodie L; Newton, Robert U

    2016-06-01

    Kicking a ball accurately over a desired distance to an intended target is arguably the most important skill to acquire in Australian Football. Therefore, understanding the potential mechanisms which underpin kicking accuracy is warranted. The aim of this study was to examine the relationship between leg mass, leg composition and foot velocity on kicking accuracy in Australian Football. Thirty-one Australian Footballers (n = 31; age: 22.1 ± 2.8 years; height: 1.81 ± 0.07 m; weight: 85.1 ± 13.0 kg; BMI: 25.9 ± 3.2) each performed ten drop punt kicks over twenty metres to a player target. Athletes were separated into accurate (n = 15) and inaccurate (n = 16) kicking groups. Leg mass characteristics were assessed using whole body DXA scans. Foot velocity was determined using a ten-camera optoelectronic, three-dimensional motion capture system. Interactions between leg mass and foot velocity evident within accurate kickers only (r = -0.670 to -0.701). Relative lean mass was positively correlated with kicking accuracy (r = 0.631), while no relationship between foot velocity and kicking accuracy was evident in isolation (r = -0.047 to -0.083). Given the evident importance of lean mass, and its interaction with foot velocity for accurate kickers; future research should explore speed-accuracy, impulse-variability, limb co-ordination and foot-ball interaction constructs in kicking using controlled with-in subject studies to examine the effects of resistance training and skill acquisition programs on the development of kicking accuracy. Key pointsAccurate kickers expressed a very strong inverse relationship between leg mass and foot velocity. Inaccurate kickers were unable to replicate this, with greater volatility in their performance, indicating an ability of accurate kickers to mediate foot velocity to compensate for leg mass in order to deliver the ball over the required distance.Accurate kickers exhibited larger quantities of relative lean mass and lower quantities

  19. Leg muscles activities during hyperventilation following a cycling exercise.

    Science.gov (United States)

    David, P; Mora, I; Terrien, J; Lelard, T; Petitjean, M

    2010-01-01

    The goal of this study was to establish how increased ventilation modifies postural stability, as characterized by body sway and leg muscle activities. Twelve healthy subjects had to perform six 30-second postural tests: one pre-exercise test while breathing gently and then one test every minute for the five minutes immediately following a maximum-intensity, incremental cycling exercise test. Subjects were asked to maintain an upright stance on a force plate for 30 s, with their eyes open. Movement of the centre of pressure in the sagittal plane was monitored in the time and spectral domains. Myoelectric activities of the soleus and tibialis anterior muscles were recorded using surface electromyography. Ventilatory parameters were measured with a portable, telemetric device. Postural changes related to respiratory variations were quantified by coherence analysis. The results showed that hyperventilation induced by exercise was accompanied by a significant increase in postural parameters, indicating a reduction in postural stability following a change in ventilatory drive. Coherence analysis confirmed the ventilatory origin of the postural oscillations. The results suggest that ventilation may be an important factor in postural disturbance during physical activity. The observed increases in leg muscle activities were most likely related to musculo-articular stiffening.

  20. The extensor tibiae muscle of the stick insect: biomechanical properties of an insect walking leg muscle.

    Science.gov (United States)

    Guschlbauer, Christoph; Scharstein, Hans; Büschges, Ansgar

    2007-03-01

    We investigated the properties of the extensor tibiae muscle of the stick insect (Carausius morosus) middle leg. Muscle geometry of the middle leg was compared to that of the front and hind legs and to the flexor tibiae, respectively. The mean length of the extensor tibiae fibres is 1.41+/-0.23 mm and flexor fibres are 2.11+/-0.30 mm long. The change of fibre length with joint angle was measured and closely follows a cosine function. Its amplitude gives effective moment arm lengths of 0.28+/-0.02 mm for the extensor and 0.56+/-0.04 mm for the flexor. Resting extensor tibiae muscle passive tonic force increased from 2 to 5 mN in the maximum femur-tibia (FT)-joint working range when stretched by ramps. Active muscle properties were measured with simultaneous activation (up to 200 pulses s(-1)) of all three motoneurons innervating the extensor tibiae, because this reflects most closely physiological muscle activation during leg swing. The force-length relationship corresponds closely to the typical characteristic according to the sliding filament hypothesis: it has a plateau at medium fibre lengths, declines nearly linearly in force at both longer and shorter fibre lengths, and the muscle's working range lies in the short to medium fibre length range. Maximum contraction velocity showed a similar relationship. The force-velocity relationship was the traditional Hill curve hyperbola, but deviated from the hyperbolic shape in the region of maximum contraction force close to the isometric contraction. Step-like changes in muscle length induced by loaded release experiments characterised the non-linear series elasticity as a quadratic spring.

  1. Improved Ventilatory Efficiency with Locomotor Muscle Afferent Inhibition is Strongly Associated with Leg Composition in Heart Failure.

    Science.gov (United States)

    Keller-Ross, Manda L; Johnson, Bruce D; Carter, Rickey E; Joyner, Michael J; Eisenach, John H; Curry, Timothy B; Olson, Thomas P

    2016-01-01

    Skeletal muscle atrophy contributes to increased afferent feedback (group III and IV) and may influence ventilatory control (high VE/VCO2 slope) in heart failure (HF). This study examined the influence of muscle mass on the change in VE/VCO2 with afferent neural block during exercise in HF. 17 participants [9 HF (60±6 yrs) and 8 controls (CTL) (63±7 yrs, mean±SD)] completed 3 sessions. Session 1: dual energy x-ray absorptiometry and graded cycle exercise to volitional fatigue. Sessions 2 and 3: 5 min of constant-work cycle exercise (65% of peak power) randomized to lumbar intrathecal injection of fentanyl (afferent blockade) or placebo. Ventilation (VE) and gas exchange (oxygen consumption, VO2; carbon dioxide production, VCO2) were measured. Peak work and VO2 were lower in HF (pLeg fat was greater in HF (34.4±3.0 and 26.3±1.8%) and leg muscle mass was lower in HF (63.0±2.8 and 70.4±1.8%, respectively, pleg muscle mass (r2=0.58, pleg fat mass (r2=0.73, pleg muscle mass had the greatest improvement in VE/VCO2 with afferent blockade with leg fat mass being the only predictor for the improvement in VE/VCO2 slope. Both leg muscle mass and fat mass are important contributors to ventilatory abnormalities and strongly associated to improvements in VE/VCO2 slope with locomotor afferent inhibition in HF. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  2. Glucose Uptake Is Decreased in Affected Lower Leg Muscles of Hemiparetic Persons during Level Walking.

    Science.gov (United States)

    Oi, Naoyuki; Itoh, Masatoshi; Tobimatsu, Yoshiko; Konno, Shinichi; Kikuchi, Shinichi; Iwaya, Tsutomu

    2015-12-01

    Stroke patients suffer from gait disturbance due to altered leg muscle actions. Many kinesiological studies have investigated muscle actions, but the metabolic activity of muscles in stroke patients remains to be investigated. We therefore evaluated energy consumption in lower extremity muscles during level walking in hemiparetic individuals. Glucose uptake was measured by positron emission tomography (PET) using (18)F-fluorodeoxyglucose ((18)F-FDG) in eight hemiparetic (mean age: 56 years) and 11 healthy (mean age: 26 years) participants. Standardized uptake ratio (SUR) was computed in each muscle to express the (18)F-FDG-uptake level. SUR was compared across gluteal, thigh, and lower leg muscles and across individual muscles within each muscle group. For each muscle, SUR was compared among the paretic limb of hemiparetic participants, the non-paretic limb of hemiparetic participants, and the right limb of healthy participants. In paretic limbs, mean SUR did not differ between the three muscle groups, or between individual muscles within each muscle group. SURs of paretic lower leg muscles and gluteus minimus muscle were significantly smaller than those of non-paretic limb and healthy participants (p limb of hemiparetic participants, SUR of the lower leg muscles was larger than that of the thigh muscles (p muscles were larger in the non-paretic limb of hemiparetic participants, compared to the right limb of healthy participants (p lower extremity muscles during level walking in hemiparetic individuals.

  3. Arm and leg substrate utilization and muscle adaptation after prolonged low-intensity training

    DEFF Research Database (Denmark)

    Helge, Jørn Wulff

    2010-01-01

    This review will focus on current data where substrate metabolism in arm and leg muscle is investigated and discuss the presence of higher carbohydrate oxidation and lactate release observed during arm compared with leg exercise. Furthermore, a basis for a possible difference in substrate...... partitioning between endogenous and exogenous substrate during arm and leg exercise will be debated. Moreover the review will probe if differences between arm and leg muscle are merely a result of different training status rather than a qualitative difference in limb substrate regulation. Along this line...... the review will address the available studies on low-intensity training performed separately with arm or legs or as whole-body training to evaluate if this leads to different adaptations in arm and leg muscle resulting in different substrate utilization patterns during separate arm or leg exercise...

  4. Possibility of leg muscle hypertrophy by ambulation in older adults: a brief review.

    Science.gov (United States)

    Ozaki, Hayao; Loenneke, Jeremy P; Thiebaud, Robert S; Stager, Joel M; Abe, Takashi

    2013-01-01

    It is known that ambulatory exercises such as brisk walking and jogging are potent stimuli for improving aerobic capacity, but it is less understood whether ambulatory exercise can increase leg muscle size and function. The purpose of this brief review is to discuss whether or not ambulatory exercise elicits leg muscle hypertrophy in older adults. Daily ambulatory activity with moderate (>3 metabolic equivalents [METs], which is defined as the ratio of the work metabolic rate to the resting metabolic rate) intensity estimated by accelerometer is positively correlated with lower body muscle size and function in older adults. Although there is conflicting data on the effects of short-term training, it is possible that relatively long periods of walking, jogging, or intermittent running for over half a year can increase leg muscle size among older adults. In addition, slow-walk training with a combination of leg muscle blood flow restriction elicits muscle hypertrophy only in the blood flow restricted leg muscles. Competitive marathon running and regular high intensity distance running in young and middle-aged adults may not produce leg muscle hypertrophy due to insufficient recovery from the damaging running bout, although there have been no studies that have investigated the effects of running on leg muscle morphology in older subjects. It is clear that skeletal muscle hypertrophy can occur independently of exercise mode and load.

  5. Nutritional interventions to preserve skeletal muscle mass

    NARCIS (Netherlands)

    Backx, Evelien M.P.

    2016-01-01

    Muscle mass is the main predictor for muscle strength and physical function. The amount of muscle mass can decline rapidly during periods of reduced physical activity or during periods of energy intake restriction. For athletes, it is important to maintain muscle mass, since the loss of muscle is

  6. Relationship between Leg Mass, Leg Composition and Foot Velocity on Kicking Accuracy in Australian Football

    Directory of Open Access Journals (Sweden)

    Nicolas H. Hart, Jodie L. Cochrane, Tania Spiteri, Sophia Nimphius, Robert U. Newton

    2016-06-01

    Full Text Available Kicking a ball accurately over a desired distance to an intended target is arguably the most important skill to acquire in Australian Football. Therefore, understanding the potential mechanisms which underpin kicking accuracy is warranted. The aim of this study was to examine the relationship between leg mass, leg composition and foot velocity on kicking accuracy in Australian Football. Thirty-one Australian Footballers (n = 31; age: 22.1 ± 2.8 years; height: 1.81 ± 0.07 m; weight: 85.1 ± 13.0 kg; BMI: 25.9 ± 3.2 each performed ten drop punt kicks over twenty metres to a player target. Athletes were separated into accurate (n = 15 and inaccurate (n = 16 kicking groups. Leg mass characteristics were assessed using whole body DXA scans. Foot velocity was determined using a ten-camera optoelectronic, three-dimensional motion capture system. Interactions between leg mass and foot velocity evident within accurate kickers only (r = -0.670 to -0.701. Relative lean mass was positively correlated with kicking accuracy (r = 0.631, while no relationship between foot velocity and kicking accuracy was evident in isolation (r = -0.047 to -0.083. Given the evident importance of lean mass, and its interaction with foot velocity for accurate kickers; future research should explore speed-accuracy, impulse-variability, limb co-ordination and foot-ball interaction constructs in kicking using controlled with-in subject studies to examine the effects of resistance training and skill acquisition programs on the development of kicking accuracy.

  7. Periodic leg movement, nasal CPAP, and expiratory muscles.

    Science.gov (United States)

    Seo, Won Hee; Guilleminault, Christian

    2012-07-01

    Periodic leg movements (PLMs) may appear during nasal CPAP titration, persisting despite the elimination of hypopneas. Systematic recordings of expiratory abdominal muscles on the right and left sides with surface electromyographic (EMG) electrodes lateral to navel, and close from the lateral side of abdomen, were added during nasal CPAP titration for treatment of obstructive sleep apnea (OSA). Positive airway pressure was titrated during nocturnal polysomnography, based on analysis of the flow curve derived from the CPAP equipment and EEG analysis, including persistence of phases A2 and A3 of the cyclic alternating pattern (CAP). The requirement was to eliminate American Association of Sleep Medicine (AASM)-defined hypopnea and also flow limitation and abnormal EEG patterns. When CPAP reached valid results, it was lowered at the time of awakening by 2 or 3 cm H(2)O, and titration was performed again. Data collected during a 7-month period on adults with a prior diagnosis of OSA who had received treatment with nasal CPAP regardless of age and sex were rendered anonymous and were retrospectively rescored by a blinded investigator. Eighty-one successively seen patients with PLMs during CPAP titration were investigated. Elimination of AASM-defined hypopnea was not sufficient to eliminate the PLMs observed during the titration; higher CPAP eliminated flow limitation and CAP phases A2 and A3 and persisting PLMs. PLMs were associated with simultaneous EMG bursts in expiratory abdominal muscles. The presence of PLMs during CPAP titration indicates the persistence of sleep-disordered breathing. PLMs during CPAP titration are related to the presence of abdominal expiratory muscle activity.

  8. Changes in lower extremity muscle mass and muscle strength after weight loss in obese men: A prospective study.

    Science.gov (United States)

    Kim, Bokun; Tsujimoto, Takehiko; So, Rina; Tanaka, Kiyoji

    2015-01-01

    Obesity is not only associated with internal diseases but also with surgical problems. Surgical diseases related to obesity frequently occur in the load bearing joints of the lower limbs. To decrease the occurrence of surgical diseases related to obesity, weight loss has been recommended. It is important for obese men to maintain muscle mass and muscle strength after weight loss because low muscle mass and muscle strength are also related to the occurrence of surgical diseases. To date, the importance of muscle mass and muscle strength after weight loss in obese men has been underappreciated. The purpose of this study was to investigate changes in lower extremity muscle mass and muscle strength resulting from a weight loss programme consisting of caloric restriction and exercise. All participants concurrently attended a 12-week diet class 1day/week and a 12-week exercise class 3days/week. Body weight and body composition by dual-energy X-ray absorptiometry and knee extensor strength by dynamometry were assessed. The weight loss programme led to a 14.1% weight loss accompanied by significant loss of leg muscle mass, static maximal muscle strength, dynamic maximal muscle strength and dynamic muscle endurance but not with significant loss of dynamic muscle power. Decline of muscle strength was related to a decrease in muscle mass, but not completely dependent on a decrease in muscle mass. Body weight-normalised muscle strength increased significantly. We recommend utilising resistance exercise to restore muscle mass and muscle strength in the legs after substantial weight loss. Copyright © 2015. Published by Elsevier Ltd.

  9. Leg crossing with muscle tensing, a physical counter-manoeuvre to prevent syncope, enhances leg blood flow

    NARCIS (Netherlands)

    Groothuis, Jan T.; van Dijk, Nynke; ter Woerds, Walter; Wieling, Wouter; Hopman, Maria T. E.

    2007-01-01

    In patients with orthostatic intolerance, the mechanisms to maintain BP (blood pressure) fail. A physical counter-manoeuvre to postpone or even prevent orthostatic intolerance in these patients is leg crossing combined with muscle tensing. Although the central haemodynamic effects of physical

  10. Leg crossing with muscle tensing, a physical counter-manoeuvre to prevent syncope, enhances leg blood flow.

    NARCIS (Netherlands)

    Groothuis, J.T.; Dijk, N. van; Woerds, W. ter; Wieling, W.; Hopman, M.T.E.

    2007-01-01

    In patients with orthostatic intolerance, the mechanisms to maintain BP (blood pressure) fail. A physical counter-manoeuvre to postpone or even prevent orthostatic intolerance in these patients is leg crossing combined with muscle tensing. Although the central haemodynamic effects of physical

  11. Characterizing rapid-onset vasodilation to single muscle contractions in the human leg

    Science.gov (United States)

    Credeur, Daniel P.; Holwerda, Seth W.; Restaino, Robert M.; King, Phillip M.; Crutcher, Kiera L.; Laughlin, M. Harold; Padilla, Jaume

    2014-01-01

    Rapid-onset vasodilation (ROV) following single muscle contractions has been examined in the forearm of humans, but has not yet been characterized in the leg. Given known vascular differences between the arm and leg, we sought to characterize ROV following single muscle contractions in the leg. Sixteen healthy men performed random ordered single contractions at 5, 10, 20, 40, and 60% of their maximum voluntary contraction (MVC) using isometric knee extension made with the leg above and below heart level, and these were compared with single isometric contractions of the forearm (handgrip). Single thigh cuff compressions (300 mmHg) were utilized to estimate the mechanical contribution to leg ROV. Continuous blood flow was determined by duplex-Doppler ultrasound and blood pressure via finger photoplethysmography (Finometer). Single isometric knee extensor contractions produced intensity-dependent increases in peak leg vascular conductance that were significantly greater than the forearm in both the above- and below-heart level positions (e.g., above heart level: leg 20% MVC, +138 ± 28% vs. arm 20% MVC, +89 ± 17%; P leg. Collectively, these data demonstrate the presence of a rapid and robust vasodilation to single muscle contractions in the leg that is largely independent of mechanical factors, thus establishing the leg as a viable model to study ROV in humans. PMID:25539935

  12. Shaping leg muscles in Drosophila: role of ladybird, a conserved regulator of appendicular myogenesis.

    Directory of Open Access Journals (Sweden)

    Tariq Maqbool

    Full Text Available Legs are locomotor appendages used by a variety of evolutionarily distant vertebrates and invertebrates. The primary biological leg function, locomotion, requires the formation of a specialised appendicular musculature. Here we report evidence that ladybird, an orthologue of the Lbx1 gene recognised as a hallmark of appendicular myogenesis in vertebrates, is expressed in leg myoblasts, and regulates the shape, ultrastructure and functional properties of leg muscles in Drosophila. Ladybird expression is progressively activated in myoblasts associated with the imaginal leg disc and precedes that of the founder cell marker dumbfounded. The RNAi-mediated attenuation of ladybird expression alters properties of developing myotubes, impairing their ability to grow and interact with the internal tendons and epithelial attachment sites. It also affects sarcomeric ultrastructure, resulting in reduced leg muscle performance and impaired mobility in surviving flies. The over-expression of ladybird also results in an abnormal pattern of dorsally located leg muscles, indicating different requirements for ladybird in dorsal versus ventral muscles. This differential effect is consistent with the higher level of Ladybird in ventrally located myoblasts and with positive ladybird regulation by extrinsic Wingless signalling from the ventral epithelium. In addition, ladybird expression correlates with that of FGF receptor Heartless and the read-out of FGF signalling downstream of FGF. FGF signals regulate the number of leg disc associated myoblasts and are able to accelerate myogenic differentiation by activating ladybird, leading to ectopic muscle fibre formation. A key role for ladybird in leg myogenesis is further supported by its capacity to repress vestigial and to down-regulate the vestigial-governed flight muscle developmental programme. Thus in Drosophila like in vertebrates, appendicular muscles develop from a specialised pool of myoblasts expressing

  13. Shaping leg muscles in Drosophila: role of ladybird, a conserved regulator of appendicular myogenesis.

    Science.gov (United States)

    Maqbool, Tariq; Soler, Cedric; Jagla, Teresa; Daczewska, Malgorzata; Lodha, Neha; Palliyil, Sudhir; VijayRaghavan, K; Jagla, Krzysztof

    2006-12-27

    Legs are locomotor appendages used by a variety of evolutionarily distant vertebrates and invertebrates. The primary biological leg function, locomotion, requires the formation of a specialised appendicular musculature. Here we report evidence that ladybird, an orthologue of the Lbx1 gene recognised as a hallmark of appendicular myogenesis in vertebrates, is expressed in leg myoblasts, and regulates the shape, ultrastructure and functional properties of leg muscles in Drosophila. Ladybird expression is progressively activated in myoblasts associated with the imaginal leg disc and precedes that of the founder cell marker dumbfounded. The RNAi-mediated attenuation of ladybird expression alters properties of developing myotubes, impairing their ability to grow and interact with the internal tendons and epithelial attachment sites. It also affects sarcomeric ultrastructure, resulting in reduced leg muscle performance and impaired mobility in surviving flies. The over-expression of ladybird also results in an abnormal pattern of dorsally located leg muscles, indicating different requirements for ladybird in dorsal versus ventral muscles. This differential effect is consistent with the higher level of Ladybird in ventrally located myoblasts and with positive ladybird regulation by extrinsic Wingless signalling from the ventral epithelium. In addition, ladybird expression correlates with that of FGF receptor Heartless and the read-out of FGF signalling downstream of FGF. FGF signals regulate the number of leg disc associated myoblasts and are able to accelerate myogenic differentiation by activating ladybird, leading to ectopic muscle fibre formation. A key role for ladybird in leg myogenesis is further supported by its capacity to repress vestigial and to down-regulate the vestigial-governed flight muscle developmental programme. Thus in Drosophila like in vertebrates, appendicular muscles develop from a specialised pool of myoblasts expressing ladybird/Lbx1. The

  14. Fatigue-related changes in motor-unit synchronization of quadriceps muscles within and across legs

    NARCIS (Netherlands)

    Boonstra, T.W.; Daffertshofer, A.; van Ditshuizen, J.C.; van den Heuvel, M.R.C.; Hofman, C.; Willigenburg, N.W.; Beek, P.J.

    2008-01-01

    Two experiments were conducted to examine effects of muscle fatigue on motor-unit synchronization of quadriceps muscles (rectus femoris, vastus medialis, vastus lateralis) within and between legs. We expected muscle fatigue to result in an increased common drive to different motor units of

  15. Quantitative ultrasound of lower leg and foot muscles: feasibility and reference values

    NARCIS (Netherlands)

    Verhulst, F.V.; Leeuwesteijn, A.E.; Louwerens, J.W.; Geurts, A.C.H.; Alfen, N. van; Pillen, S.

    2011-01-01

    BACKGROUND: Ultrasound is a non-invasive method to quantitatively measure various muscle parameters. Purpose of this study was to assess the feasibility of ultrasound of lower leg and foot muscles and to obtain reference values for muscle thickness (MT) and echo intensity (EI). METHODS: Ultrasound

  16. Regulation of PDH in human arm and leg muscles at rest and during intense exercise

    DEFF Research Database (Denmark)

    Kiilerich, Kristian; Birk, Jesper Bratz; Damsgaard, Rasmus

    2008-01-01

    arm cycling on two occasions and leg cycling exercise on a third day. Muscle biopsies were obtained from deltoid or triceps on the arm exercise days and from vastus lateralis on the leg cycling day. Resting PDH protein content and phosphorylation on PDH-E1 alpha sites 1 and 2 were higher (P

  17. Aberrant femoral torsion presenting with frog-leg squatting mimicking gluteal muscle contracture.

    Science.gov (United States)

    Chiang, Chia-Ling; Tsai, Meng-Yuan; Chang, Wei-Ning; Chen, Clement Kuen-Huang

    2012-04-01

    Patients with frog-leg squatting have restricted internal rotation and adduction of the affected hips during sitting or squatting. In the surgical literature, the cause generally has been presumed to arise from and be pathognomonic for gluteal muscle contracture. However, we have encountered patients with frog-leg squatting but without gluteal muscle contracture. We therefore raised the following questions: What are the imaging features of patients with frog-leg squatting? Do conditions other than gluteal muscle contracture manifest frog-leg squatting? We retrospectively reviewed the MR images of 67 patients presenting with frog-leg squatting from April 1998 to July 2010. There were four females and 63 males; their mean age was 22.2 years (range, 4-50 years). During MRI readout, we observed aberrant axes of some femoral necks and obtained additional CT to measure femoral torsion angles in 59 of the 67 patients. MR images of 27 (40%) patients had signs of gluteal muscle contracture. Twenty-two (33%) patients (40 femora) had aberrant femoral torsion, including diminished anteversion (range, 6°-0°; average, 3.9°) in 11 femora of eight patients and femoral retroversion (range, muscle contracture or aberrant femoral torsion. The observation of aberrant femoral torsion was not anticipated before imaging studies. In addition to gluteal muscle contracture, aberrant femoral torsion can be a cause of frog-leg squatting. Level II, diagnostic study. See the guidelines for Authors for a complete description of levels of evidence.

  18. Lower leg muscle density is independently associated with fall status in community-dwelling older adults.

    Science.gov (United States)

    Frank-Wilson, A W; Farthing, J P; Chilibeck, P D; Arnold, C M; Davison, K S; Olszynski, W P; Kontulainen, S A

    2016-07-01

    Muscle density is a risk factor for fractures in older adults; however, its association with falls is not well described. After adjusting for biologically relevant confounding factors, a unit decrease in muscle density was associated with a 17 % increase in odds of reporting a fall, independent of functional mobility. Falls are the leading cause of injury, disability, and fractures in older adults. Low muscle density (i.e., caused by muscle adiposity) and functional mobility have been identified as risk factors for incident disability and fractures in older adults; however, it is not known if these are also independently associated with falls. The purpose of this study was to explore the associations of muscle density and functional mobility with fall status. Cross-sectional observational study of 183 men and women aged 60-98 years. Descriptive data, including a 12-month fall recall, Timed Up and Go (TUG) test performance, lower leg muscle area, and density. Odds ratio (OR) of being a faller were calculated, adjusted for age, sex, body mass index, general health status, diabetes, and comorbidities. Every mg/cm(3) increase in muscle density (mean 70.2, SD 2.6 mg/cm(3)) independently reduced the odds of being a faller by 19 % (OR 0.81 [95 % CI 0.67 to 0.97]), and every 1 s longer TUG test time (mean 9.8, SD 2.6 s) independently increased the odds by 17 % (OR 1.17 [95 % CI 1.01 to 1.37]). When both muscle density and TUG test time were included in the same model, only age (OR 0.93 [95 % CI 0.87 to 0.99]) and muscle density (OR 0.83 [95 % CI 0.69 to 0.99]) were independently associated with fall status. Muscle density was associated with fall status, independent of functional mobility. Muscle density may compliment functional mobility tests as a biometric outcome for assessing fall risk in well-functioning older adults.

  19. Leg Strength and Lean Mass Symmetry Influences Kicking Performance in Australian Football

    Science.gov (United States)

    Hart, Nicolas H.; Nimphius, Sophia; Spiteri, Tania; Newton, Robert U.

    2014-01-01

    Differential loading patterns during game-based participation may produce or exacerbate strength imbalances between the lower limbs. It is currently unknown whether such imbalances are functionally beneficial or detrimental to performance. This study assessed the influence of lower limb strength and lean mass symmetry on kicking accuracy in Australian Football. Thirty-one Australian footballers were required to perform a kicking assessment, producing ten drop punt kicks over twenty metres to a player target. Athletes were subsequently separated into accurate (n = 15) and inaccurate (n = 16) groups, with lower-body lean mass assessed using whole body DXA scans, and lower-body strength assessed using an isometric protocol. Accurate kickers demonstrated significantly higher relative lean mass (~8% to 16%; p = 0. 001 to 0.004) and significantly lower relative fat mass (~21% to 40%; p = 0.001 to 0.024) than inaccurate kickers. Accurate kickers did not contain any significant difference in lean mass or unilateral strength between lower limbs. Inaccurate kickers displayed significant asymmetry in lean mass (~3%; p ≤ 0.003), producing significant imbalances in strength (~8%; p ≤ 0.002) highlighting a deficiency in their support leg. Greater relative strength and improved lower limb symmetry in strength and muscularity could increase the capacity of an athlete to be technically proficient in favour of greater accuracy. Key Points Strength deficits in the support leg may lead to inaccurate kicking outcomes. An asymmetry of 3% in lean mass generated an 8% imbalance in leg strength. Greater levels of relative lower-body strength and muscle mass are associated with improved kicking accuracy performance. PMID:24570620

  20. Leg strength and lean mass symmetry influences kicking performance in Australian football.

    Science.gov (United States)

    Hart, Nicolas H; Nimphius, Sophia; Spiteri, Tania; Newton, Robert U

    2014-01-01

    Differential loading patterns during game-based participation may produce or exacerbate strength imbalances between the lower limbs. It is currently unknown whether such imbalances are functionally beneficial or detrimental to performance. This study assessed the influence of lower limb strength and lean mass symmetry on kicking accuracy in Australian Football. Thirty-one Australian footballers were required to perform a kicking assessment, producing ten drop punt kicks over twenty metres to a player target. Athletes were subsequently separated into accurate (n = 15) and inaccurate (n = 16) groups, with lower-body lean mass assessed using whole body DXA scans, and lower-body strength assessed using an isometric protocol. Accurate kickers demonstrated significantly higher relative lean mass (~8% to 16%; p = 0. 001 to 0.004) and significantly lower relative fat mass (~21% to 40%; p = 0.001 to 0.024) than inaccurate kickers. Accurate kickers did not contain any significant difference in lean mass or unilateral strength between lower limbs. Inaccurate kickers displayed significant asymmetry in lean mass (~3%; p ≤ 0.003), producing significant imbalances in strength (~8%; p ≤ 0.002) highlighting a deficiency in their support leg. Greater relative strength and improved lower limb symmetry in strength and muscularity could increase the capacity of an athlete to be technically proficient in favour of greater accuracy. Key PointsStrength deficits in the support leg may lead to inaccurate kicking outcomes.An asymmetry of 3% in lean mass generated an 8% imbalance in leg strength.Greater levels of relative lower-body strength and muscle mass are associated with improved kicking accuracy performance.

  1. Growth responses of breast and leg muscles to essential amino acids in broiler chicks.

    Science.gov (United States)

    Mehri, M; Bagherzadeh-Kasmani, F; Rokouei, M

    2016-03-01

    The first three essential amino acids (EAA) for broilers including methionine (Met), lysine (Lys) and threonine (Thr) may greatly influence the growth of chick muscles at early stages of life. In order to survey the potential effects of those EAA on growth muscles, a rotatable three-variable central composite design (CCD) was conducted to track the interrelationships of dietary digestible Met (dMet), Lys (dLys) and Thr (dThr) for optimization of processing yields in broiler chicks using response surface methodology. A total of 60 floor pens of six birds each were assigned to 15 dietary treatments based on CCD containing five levels of dMet (0.416% to 0.584% of diet), dLys (0.881% to 1.319% of diet) and dThr (0.532% to 0.868% of diet) from 3 to 16 days of age. Experimental treatments significantly affected breast mass (BM) and leg mass (LM) of the birds (Pdiet, and maximum LM point may be achieved with 0.58%, 1.09% and 0.70% of dMet, dLys and dThr, respectively, in diet. The resultant ideal ratios of dMet and dThr to dLys were 55% and 72% for BM; 53% and 64% for LM. Moreover, sensitivity analysis showed that the most important amino acids in BM and LM models were Lys and Thr, respectively. In conclusion, providing these three amino acid for BM optimization may warrant LM optimization and higher ideal ratios of dMet and dThr for breast muscle may indicate the higher importance of these EAA in this muscle than those in thigh muscle.

  2. THE ROLE OF LEG AND TRUNK MUSCLES PROPRIOCEPTION ON STATIC AND DYNAMIC POSTURAL CONTROL

    Directory of Open Access Journals (Sweden)

    SEYED Hossein Hosseinimehr

    2010-04-01

    Full Text Available The proprioception information is a prerequisite for balance, body’s navigation system, and the movement coordinator. Due to changes between the angles of ankle, knee, and hip joints the aforementioned information are important in the coordination of the limbs and postural balance. The aim of this study was to investigate therole of leg and trunk muscles proprioception on static and dynamic postural control. Thirty males students of physical education and sport sciences (age =21.23 ± 2.95 years, height = 170.4 ± 5.1 cm, and weight = 70.7 ± 5.6 kg participated in this study volunteered. Vibration (100HZ was used to disturb of proprioception. Vibrationoperated on leg muscle (gasterocnemius and trunk muscles (erector spine muscle, at L1 level. Leg stance time and Star Excursion Balance Test were used for evaluation of static and dynamic postural control respectively.Subjects performed pre and post (with operated vibration leg stance time and star excursion balance test. Paired sample test used for investigation the effect of vibration on leg and trunk muscles in static and dynamic postural control. Result of this study showed in static postural control, there is no significant difference between pre and post test (operated vibration in leg and trunk muscles (p≤0.05. In contrast there is significant difference indynamic postural control between pre and post test in leg muscles in 8 directions of star excursion balance test (p≤0.05 while there is only significant difference in trunk muscle in antrolateral and lateral of star excursion balance test (p≤0.05. During physical training such conditions like fatigue and injury can disturbproprioceptions’ information. Thus, due to the importance of this information we recommend that coaches'additionally specific trainings any sport used specific exercises to enhance the proprioception information

  3. A Biological Micro Actuator: Graded and Closed-Loop Control of Insect Leg Motion by Electrical Stimulation of Muscles

    Science.gov (United States)

    Cao, Feng; Zhang, Chao; Vo Doan, Tat Thang; Li, Yao; Sangi, Daniyal Haider; Koh, Jie Sheng; Huynh, Ngoc Anh; Aziz, Mohamed Fareez Bin; Choo, Hao Yu; Ikeda, Kazuo; Abbeel, Pieter; Maharbiz, Michel M.; Sato, Hirotaka

    2014-01-01

    In this study, a biological microactuator was demonstrated by closed-loop motion control of the front leg of an insect (Mecynorrhina torquata, beetle) via electrical stimulation of the leg muscles. The three antagonistic pairs of muscle groups in the front leg enabled the actuator to have three degrees of freedom: protraction/retraction, levation/depression, and extension/flexion. We observed that the threshold amplitude (voltage) required to elicit leg motions was approximately 1.0 V; thus, we fixed the stimulation amplitude at 1.5 V to ensure a muscle response. The leg motions were finely graded by alternation of the stimulation frequencies: higher stimulation frequencies elicited larger leg angular displacement. A closed-loop control system was then developed, where the stimulation frequency was the manipulated variable for leg-muscle stimulation (output from the final control element to the leg muscle) and the angular displacement of the leg motion was the system response. This closed-loop control system, with an optimized proportional gain and update time, regulated the leg to set at predetermined angular positions. The average electrical stimulation power consumption per muscle group was 148 µW. These findings related to and demonstrations of the leg motion control offer promise for the future development of a reliable, low-power, biological legged machine (i.e., an insect–machine hybrid legged robot). PMID:25140875

  4. A biological micro actuator: graded and closed-loop control of insect leg motion by electrical stimulation of muscles.

    Directory of Open Access Journals (Sweden)

    Feng Cao

    Full Text Available In this study, a biological microactuator was demonstrated by closed-loop motion control of the front leg of an insect (Mecynorrhina torquata, beetle via electrical stimulation of the leg muscles. The three antagonistic pairs of muscle groups in the front leg enabled the actuator to have three degrees of freedom: protraction/retraction, levation/depression, and extension/flexion. We observed that the threshold amplitude (voltage required to elicit leg motions was approximately 1.0 V; thus, we fixed the stimulation amplitude at 1.5 V to ensure a muscle response. The leg motions were finely graded by alternation of the stimulation frequencies: higher stimulation frequencies elicited larger leg angular displacement. A closed-loop control system was then developed, where the stimulation frequency was the manipulated variable for leg-muscle stimulation (output from the final control element to the leg muscle and the angular displacement of the leg motion was the system response. This closed-loop control system, with an optimized proportional gain and update time, regulated the leg to set at predetermined angular positions. The average electrical stimulation power consumption per muscle group was 148 µW. These findings related to and demonstrations of the leg motion control offer promise for the future development of a reliable, low-power, biological legged machine (i.e., an insect-machine hybrid legged robot.

  5. Lower extremity muscle activation onset times during the transition from double-leg stance to single-leg stance in anterior cruciate ligament reconstructed subjects.

    Science.gov (United States)

    Dingenen, Bart; Janssens, Luc; Claes, Steven; Bellemans, Johan; Staes, Filip F

    2016-06-01

    Previous studies mainly focused on muscles at the operated knee after anterior cruciate ligament reconstruction, less on muscles around other joints of the operated and non-operated leg. The aim of this study was to investigate muscle activation onset times during the transition from double-leg stance to single-leg stance in anterior cruciate ligament reconstructed subjects. Lower extremity muscle activation onset times of both legs of 20 fully returned to sport anterior cruciate ligament reconstructed subjects and 20 non-injured control subjects were measured during the transition from double-leg stance to single-leg stance in eyes open and eyes closed conditions. Analysis of covariance (ANCOVA) was used to evaluate differences between groups and differences between legs within both groups, while controlling for peak center of pressure velocity. Significantly delayed muscle activation onset times were found in the anterior cruciate ligament reconstructed group compared to the control group for gluteus maximus, gluteus medius, vastus medialis obliquus, medial hamstrings, lateral hamstrings and gastrocnemius in both eyes open and eyes closed conditions (Panterior cruciate ligament reconstructed group, no significant different muscle activation onset times were found between the operated and non-operated leg (P>.05). Despite completion of rehabilitation and full return to sport, the anterior cruciate ligament reconstructed group showed neuromuscular control deficits that were not limited to the operated knee joint. Clinicians should focus on relearning multi-segmental anticipatory neuromuscular control strategies after anterior cruciate ligament reconstruction. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Postnatal development of fiber type composition in rabbit jaw and leg muscles

    NARCIS (Netherlands)

    Korfage, J. A. M.; Helmers, R.; Matignon, M. de Goüyon; van Wessel, T.; Langenbach, G. E. J.; van Eijden, T. M. G. J.

    2009-01-01

    We examined the difference in fiber type composition and cross-sectional areas during postnatal development in male rabbit jaw muscles and compared these with changes in leg muscles. The myosin heavy chain (MyHC) content of the fibers was determined by immunohistochemistry. No fiber type difference

  7. Impact of Running Exercise Duration on Leg Muscle Strength among the people Joining Indorunners Bandung Community

    Directory of Open Access Journals (Sweden)

    Agaprita Eunike Sirait

    2017-03-01

    Full Text Available Background: Indorunners Bandung is a community for runners that has a routine exercise schedule for running around the city of Bandung. Exercise, like running, if is conducted in an accurate duration may improve physical fitness. One of the aspects of physical fitness is leg muscles strength. Many people fail to fathom the importance of exercise duration, so, they fail to get the benefit. The aim of this study was to discover the impact of running exercise duration on leg muscles strength among the people joining Indorunners Bandung community. Methods: A comparative study was conducted to 41 people, 31 males and 10 females, of Indorunners Bandung community from September to November 2015. Each participant filled a questionnaire about his/her personal data, and then was grouped by his/her duration of exercise per week, which were 150 minutes/week, 150–299 minutes/week, and 300 minutes/week or more. The respondents were measured for their leg muscles strength. The data collected were analyzed using ANOVA test. Results: There was significant difference of lower extremities muscle strength both in men (p<0.001 and women (p=0.029. These results showed that there was a difference in leg muscles strength among the people joining Indorunners Bandung community with different exercise duration per week. Conclusions: There is a difference in leg muscles strength among the people joining Indorunners Bandung community with different exercise duration per week.

  8. A Biological Micro Actuator: Graded and Closed-Loop Control of Insect Leg Motion by Electrical Stimulation of Muscles

    OpenAIRE

    Cao, Feng; Zhang, Chao; Vo Doan, Tat Thang; Li, Yao; Sangi, Daniyal Haider; Koh, Jie Sheng; Huynh, Ngoc Anh; Aziz, Mohamed Fareez Bin; Choo, Hao Yu; Ikeda, Kazuo; Abbeel, Pieter; Maharbiz, Michel M.; Sato, Hirotaka

    2014-01-01

    In this study, a biological microactuator was demonstrated by closed-loop motion control of the front leg of an insect (Mecynorrhina torquata, beetle) via electrical stimulation of the leg muscles. The three antagonistic pairs of muscle groups in the front leg enabled the actuator to have three degrees of freedom: protraction/retraction, levation/depression, and extension/flexion. We observed that the threshold amplitude (voltage) required to elicit leg motions was approximately 1.0 V; thus, ...

  9. Normal mitochondrial function and increased fat oxidation capacity in leg and arm muscles in obese humans

    DEFF Research Database (Denmark)

    Ara, I; Larsen, S; Stallknecht, Bente Merete

    2011-01-01

    was that fat oxidation during exercise might be differentially preserved in leg and arm muscles after weight loss.Methods:Indirect calorimetry was used to calculate fat and carbohydrate oxidation during both progressive arm-cranking and leg-cycling exercises. Muscle biopsy samples were obtained from musculus......, and plasma leptin was higher in O than in PO and C.Conclusions:In O subjects, maximal fat oxidation during exercise and the eliciting relative exercise intensity are increased. This is associated with higher intramuscular triglyceride levels and higher resting non esterified fatty acid (NEFA) concentrations...... deltoideus (m. deltoideus) and m. vastus lateralis muscles. Fibre-type composition, enzyme activity and O(2) flux capacity of saponin-permeabilized muscle fibres were measured, the latter by high-resolution respirometry.Results:During the graded exercise tests, peak fat oxidation during leg cycling...

  10. Muscle interstitial ATP and norepinephrine concentrations in the human leg during exercise and ATP infusion

    DEFF Research Database (Denmark)

    Mortensen, Stefan P.; Gonzalez-Alonso, Jose; Nielsen, Jens Jung

    2009-01-01

    ATP and NE concentrations to gain insight into the interstitial and intravascular mechanisms by which ATP causes muscle vasodilation and sympatholysis. Leg hemodynamics and muscle interstitial nucleotide and norepinephrine (NE) concentrations were measured during: 1) femoral arterial ATP infusion (0......, respectively (Pcontracting muscle (Pmuscle, whereas interstitial NE concentrations increased similarly in both active...... and inactive muscles. These results suggest that the vasodilatory and sympatholytic effects of intraluminal ATP are mainly mediated via endothelial prinergic receptors. Intraluminal ATP and muscle contractions appear to modulate sympathetic nerve activity by inhibiting the effect of NE rather than blunting its...

  11. The role of active muscle mass in determining the magnitude of peripheral fatigue during dynamic exercise.

    Science.gov (United States)

    Rossman, Matthew J; Garten, Ryan S; Venturelli, Massimo; Amann, Markus; Richardson, Russell S

    2014-06-15

    Greater peripheral quadriceps fatigue at the voluntary termination of single-leg knee-extensor exercise (KE), compared with whole-body cycling, has been attributed to confining group III and IV skeletal muscle afferent feedback to a small muscle mass, enabling the central nervous system (CNS) to tolerate greater peripheral fatigue. However, as task specificity and vastly differing systemic challenges may have complicated this interpretation, eight males were studied during constant workload trials to exhaustion at 85% of peak workload during single-leg and double-leg KE. It was hypothesized that because of the smaller muscle mass engaged during single-leg KE, a greater magnitude of peripheral quadriceps fatigue would be present at exhaustion. Vastus lateralis integrated electromyogram (iEMG) signal relative to the first minute of exercise, preexercise to postexercise maximal voluntary contractions (MVCs) of the quadriceps, and twitch-force evoked by supramaximal magnetic femoral nerve stimulation (Qtw,pot) quantified peripheral quadriceps fatigue. Trials performed with single-leg KE (8.1 ± 1.2 min; 45 ± 4 W) resulted in significantly greater peripheral quadriceps fatigue than double-leg KE (10 ± 1.3 min; 83 ± 7 W), as documented by changes in the iEMG signal (147 ± 24 vs. 85 ± 13%), MVC (-25 ± 3 vs. -12 ± 3%), and Qtw,pot (-44 ± 6 vs. -33 ± 7%), for single-leg and double-leg KE, respectively. Therefore, avoiding concerns over task specificity and cardiorespiratory limitations, this study reveals that a reduction in muscle mass permits the development of greater peripheral muscle fatigue and supports the concept that the CNS tolerates a greater magnitude of peripheral fatigue when the source of group III/IV afferent feedback is limited to a small muscle mass.

  12. Optimizing the Distribution of Leg Muscles for Vertical Jumping.

    Directory of Open Access Journals (Sweden)

    Jeremy D Wong

    Full Text Available A goal of biomechanics and motor control is to understand the design of the human musculoskeletal system. Here we investigated human functional morphology by making predictions about the muscle volume distribution that is optimal for a specific motor task. We examined a well-studied and relatively simple human movement, vertical jumping. We investigated how high a human could jump if muscle volume were optimized for jumping, and determined how the optimal parameters improve performance. We used a four-link inverted pendulum model of human vertical jumping actuated by Hill-type muscles, that well-approximates skilled human performance. We optimized muscle volume by allowing the cross-sectional area and muscle fiber optimum length to be changed for each muscle, while maintaining constant total muscle volume. We observed, perhaps surprisingly, that the reference model, based on human anthropometric data, is relatively good for vertical jumping; it achieves 90% of the jump height predicted by a model with muscles designed specifically for jumping. Alteration of cross-sectional areas-which determine the maximum force deliverable by the muscles-constitutes the majority of improvement to jump height. The optimal distribution results in large vastus, gastrocnemius and hamstrings muscles that deliver more work, while producing a kinematic pattern essentially identical to the reference model. Work output is increased by removing muscle from rectus femoris, which cannot do work on the skeleton given its moment arm at the hip and the joint excursions during push-off. The gluteus composes a disproportionate amount of muscle volume and jump height is improved by moving it to other muscles. This approach represents a way to test hypotheses about optimal human functional morphology. Future studies may extend this approach to address other morphological questions in ethological tasks such as locomotion, and feature other sets of parameters such as properties of

  13. Recovery of atrophic leg muscles in the hemiplegics due to cerebrovascular accidents

    International Nuclear Information System (INIS)

    Odajima, Natsu; Ishiai, Sumio; Okiyama, Ryouichi; Furukawa, Tetsuo; Tsukagoshi, Hiroshi.

    1988-01-01

    Thirty-five patients with hemiplegia due to cerebrovascular accidents were studied with regared to the muscle wastings before and after rehabilitation training. Hemiplegics were composed of 12 improved and 23 non-improved patients. The CT scan was carried out at the midportion of the thigh and largest-diameter section of the calf. Muscle size of each cross-sectional area was measured on CT image and the increase of size (ΔS) in each muscle after training was calculated. The ΔS of quadriceps femoris was correlated with that of whole cross-section of the thigh. The gracilis in non-affected side was not correlated with that of whole muscles. In both legs, there was an increase in leg muscle size after training. These changes were nost marked in the non-affected side of the improved patients. After training the difference between the two limbs remained unchanged. Recovery of muscle wasting in both legs was seen first in the quadriceps in thigh and flexors in calf. Gracilis was relatively unchanged in comparison with other muscles. Remarkable increase of muscle size in non-affected side was worthwhile to note. (author)

  14. Bilateral differences in muscle fascicle architecture are not related to the preferred leg in jumping athletes.

    Science.gov (United States)

    Aeles, Jeroen; Lenchant, Sietske; Vanlommel, Liesbeth; Vanwanseele, Benedicte

    2017-07-01

    In many sports, athletes have a preferred leg for sport-specific tasks, such as jumping, which leads to strength differences between both legs, yet the underlying changes in force-generating mechanical properties of the muscle remain unknown. The purpose of this study was to investigate whether the muscle architecture of the medial gastrocnemius (MG) is different between both legs in well-trained jumping athletes and untrained individuals. In addition, we investigated the effect of two ankle joint positions on ultrasound muscle architecture measurements. Muscle architecture of both legs was measured in 16 athletes and 11 untrained individuals at two ankle joint angles: one with the ankle joint in a tendon slack length (TSL) angle and one in a 90° angle. Fascicle lengths and pennation angles at TSL were not different between the preferred and non-preferred legs in either group. The comparison between groups showed no difference in fascicle length, but greater pennation angles were found in the athletes (21.7° ± 0.5°) compared to the untrained individuals (19.8° ± 0.6°). Analyses of the muscle architecture at a 90° angle yielded different results, mainly in the comparison between groups. These results provide only partial support for the notion of training-induced changes in muscle architecture as only differences in pennation angles were found between athletes and untrained individuals. Furthermore, our results provide support to the recommendation to take into account the tension-length relationship and to measure muscle architecture at individually determined tendon slack joint angles.

  15. Glucose clearance is higher in arm than leg muscle in type 2 diabetes

    DEFF Research Database (Denmark)

    Olsen, David B; Sacchetti, Massimo; Dela, Flemming

    2005-01-01

    and insulin resistance may not be evenly distributed. We measured basal and insulin-mediated (1 pmol min-1 kg-1) GC simultaneously in the arm and leg in type 2 diabetes patients (TYPE 2) and controls (CON) (n=6 for both). During the clamp arterio-venous glucose extraction was higher in CON versus TYPE 2...... in the arm (6.9+/-1.0 versus 4.7+/-0.8%; mean+/-s.e.m.; P=0.029), but not in the leg (4.2+/-0.8 versus 3.1+/-0.6%). Blood flow was not different between CON and TYPE 2 but was higher (Parm versus leg (CON: 74+/-8 versus 56+/-5; TYPE 2: 87+/-9 versus 43+/-6 ml min-1 kg-1 muscle, respectively......). At basal, CON had 84% higher arm GC (P=0.012) and 87% higher leg GC (P=0.016) compared with TYPE 2. During clamp, the difference between CON and TYPE 2 in arm GC was diminished to 54% but maintained at 80% in the leg. In conclusion, this study shows that glucose clearance is higher in arm than leg muscles...

  16. Predicting muscle forces during the propulsion phase of single leg triple hop test.

    Science.gov (United States)

    Alvim, Felipe Costa; Lucareli, Paulo Roberto Garcia; Menegaldo, Luciano Luporini

    2018-01-01

    Functional biomechanical tests allow the assessment of musculoskeletal system impairments in a simple way. Muscle force synergies associated with movement can provide additional information for diagnosis. However, such forces cannot be directly measured noninvasively. This study aims to estimate muscle activations and forces exerted during the preparation phase of the single leg triple hop test. Two different approaches were tested: static optimization (SO) and computed muscle control (CMC). As an indirect validation, model-estimated muscle activations were compared with surface electromyography (EMG) of selected hip and thigh muscles. Ten physically healthy active women performed a series of jumps, and ground reaction forces, kinematics and EMG data were recorded. An existing OpenSim model with 92 musculotendon actuators was used to estimate muscle forces. Reflective markers data were processed using the OpenSim Inverse Kinematics tool. Residual Reduction Algorithm (RRA) was applied recursively before running the SO and CMC. For both, the same adjusted kinematics were used as inputs. Both approaches presented similar residuals amplitudes. SO showed a closer agreement between the estimated activations and the EMGs of some muscles. Due to inherent EMG methodological limitations, the superiority of SO in relation to CMC can be only hypothesized. It should be confirmed by conducting further studies comparing joint contact forces. The workflow presented in this study can be used to estimate muscle forces during the preparation phase of the single leg triple hop test and allows investigating muscle activation and coordination. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Pneumatic Artificial Muscles Force Modelling and the Position and Stiffness Control on the Knee Joint of the Musculoskeletal Leg

    OpenAIRE

    Jingtao Lei; Jianmin Zhu

    2017-01-01

    Pneumatic artificial muscles (PAMs) have properties similar to biological muscle and are widely used in robotics as actuators. A musculoskeletal leg mechanism driven by PAMs is presented in this paper. The joint stiffness of the musculoskeletal bionic leg for jumping movement needs to be analysed. The synchronous control on the position and stiffness of the joint is important to improve the flexibility of leg. The accurate force model of PAM is the foundation to achieving better control and d...

  18. Quantitation of progressive muscle fatigue during dynamic leg exercise in humans

    DEFF Research Database (Denmark)

    Fulco, C S; Lewis, S F; Frykman, Peter

    1995-01-01

    , a product of a contraction rate (1 Hz), force measured at the ankle, and distance of ankle movement from 90 degrees to 150 degrees of KE, was precisely controlled. Lack of rise in myoelectric activity in biceps femoris of the active leg during DKE and MVC was consistent with restriction of muscle action...

  19. Effect of armor and carrying load on body balance and leg muscle function.

    Science.gov (United States)

    Park, Huiju; Branson, Donna; Kim, Seonyoung; Warren, Aric; Jacobson, Bert; Petrova, Adriana; Peksoz, Semra; Kamenidis, Panagiotis

    2014-01-01

    This study investigated the impact of weight and weight distribution of body armor and load carriage on static body balance and leg muscle function. A series of human performance tests were conducted with seven male, healthy, right-handed military students in seven garment conditions with varying weight and weight distributions. Static body balance was assessed by analyzing the trajectory of center of plantar pressure and symmetry of weight bearing in the feet. Leg muscle functions were assessed by analyzing the peak electromyography amplitude of four selected leg muscles during walking. Results of this study showed that uneven weight distribution of garment and load beyond an additional 9 kg impaired static body balance as evidenced by increased sway of center of plantar pressure and asymmetry of weight bearing in the feet. Added weight on non-dominant side of the body created greater impediment to static balance. Increased garment weight also elevated peak EMG amplitude in the rectus femoris to maintain body balance and in the medial gastrocnemius to increase propulsive force. Negative impacts on balance and leg muscle function with increased carrying loads, particularly with an uneven weight distribution, should be stressed to soldiers, designers, and sports enthusiasts. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Leg muscle activation during gait in Parkinson's disease : Adaptation and interlimb coordination

    NARCIS (Netherlands)

    Dietz, [No Value; Zijlstra, W; Prokop, T; Berger, W

    1995-01-01

    Adaptation in leg muscle activity and coordination between lower limbs were studied during walking on a treadmill with split belts in one group of parkinsonian patients and one of age-matched healthy subjects. Four different belt speeds (0.25/0.5/0.75/1.0 m/sec) were applied in selected combinations

  1. Effect of Ladder Drill Exercise on Speed, Surrounding, and Power Leg Muscle

    Directory of Open Access Journals (Sweden)

    Ketut Chandra Adinata Kusuma

    2017-10-01

    Full Text Available This study aimed at finding the effect of ladder drill training upon: (1 run speed, (2 agility, and (2 power of leg muscle. This study is an experimental research. This study utilized one group pre test-post test design. There were total people as the subject of this research. Data collection technique used 30-meter sprint test to measure run speed, Illinois agility test to measure agility, and vertical jump test to measure power of leg muscle. Data analysis technique which was used for normality test, homogeneity test/F-test, and T-test with significant level 5% by using SPSS 16.0.0. Based on the finding, there was effect of ladder drill training upon run speed with sig value=0.007, agility and power of leg muscle with sig value=0.000. Based on the data analysis, it could be concluded that there was significant effect of ladder drill training upon run speed, agility and power of leg muscle.

  2. Coordinated development of muscles and tendon-like structures: early interactions in the Drosophila leg

    Directory of Open Access Journals (Sweden)

    cedric esoler

    2016-02-01

    Full Text Available The formation of the musculoskeletal system is a remarkable example of tissue assembly. In both vertebrates and invertebrates, precise connectivity between muscles and skeleton (or exoskeleton via tendons or equivalent structures is fundamental for movement and stability of the body. The molecular and cellular processes underpinning muscle formation are well established and significant advances have been made in understanding tendon development. However, the mechanisms contributing to proper connection between these two tissues have received less attention. Observations of coordinated development of tendons and muscles suggest these tissues may interact during the different steps in their development. There is growing evidence that, depending on animal model and muscle type, these interactions can take place from progenitor induction to the final step of the formation of the musculoskeletal system. Here we briefly review and compare the mechanisms behind muscle and tendon interaction throughout the development of vertebrates and Drosophila before going on to discuss our recent findings on the coordinated development of muscles and tendon-like structures in Drosophila leg. By altering apodeme formation (the functional Drosophila equivalent of tendons in vertebrates during the early steps of leg development, we affect the spatial localisation of subsequent myoblasts. These findings provide the first evidence of the developmental impact of early interactions between muscle and tendon-like precursors, and confirm the appendicular Drosophila muscle system as a valuable model for studying these processes.

  3. Optimizing the Distribution of Leg Muscles for Vertical Jumping

    NARCIS (Netherlands)

    Wong, J.D.; Bobbert, M.F.; van Soest, A.J.; Gribble, P.L.; Kistemaker, D.A.

    2016-01-01

    A goal of biomechanics and motor control is to understand the design of the human musculoskeletal system. Here we investigated human functional morphology by making predictions about the muscle volume distribution that is optimal for a specific motor task. We examined a well-studied and relatively

  4. Human Leg Model Predicts Muscle Forces, States, and Energetics during Walking.

    Science.gov (United States)

    Markowitz, Jared; Herr, Hugh

    2016-05-01

    Humans employ a high degree of redundancy in joint actuation, with different combinations of muscle and tendon action providing the same net joint torque. Both the resolution of these redundancies and the energetics of such systems depend on the dynamic properties of muscles and tendons, particularly their force-length relations. Current walking models that use stock parameters when simulating muscle-tendon dynamics tend to significantly overestimate metabolic consumption, perhaps because they do not adequately consider the role of elasticity. As an alternative, we posit that the muscle-tendon morphology of the human leg has evolved to maximize the metabolic efficiency of walking at self-selected speed. We use a data-driven approach to evaluate this hypothesis, utilizing kinematic, kinetic, electromyographic (EMG), and metabolic data taken from five participants walking at self-selected speed. The kinematic and kinetic data are used to estimate muscle-tendon lengths, muscle moment arms, and joint moments while the EMG data are used to estimate muscle activations. For each subject we perform an optimization using prescribed skeletal kinematics, varying the parameters that govern the force-length curve of each tendon as well as the strength and optimal fiber length of each muscle while seeking to simultaneously minimize metabolic cost and maximize agreement with the estimated joint moments. We find that the metabolic cost of transport (MCOT) values of our participants may be correctly matched (on average 0.36±0.02 predicted, 0.35±0.02 measured) with acceptable joint torque fidelity through application of a single constraint to the muscle metabolic budget. The associated optimal muscle-tendon parameter sets allow us to estimate the forces and states of individual muscles, resolving redundancies in joint actuation and lending insight into the potential roles and control objectives of the muscles of the leg throughout the gait cycle.

  5. Computed tomographic findings of leg muscles in the hemiplegics due to cerebrovascular accidents

    International Nuclear Information System (INIS)

    Odajima, Natsu; Ishiai, Sumio; Kotera, Minoru; Furukawa, Tetsuo; Tsukagoshi, Hiroshi.

    1986-01-01

    The computed tomography (CT) scan was performed in 52 hemiplegics due to cerebrovascular accidents and 12 normal controls on the mid-portion of the thigh and the largest-diameter section of the calf. Muscle size and average CT density of the muscle were measured. The salient feature was hypertrophic gracilis muscle of the hemiplegic side. Other muscles were more atrophied with lower CT density compared with those of the contralateral side. The size of the quadriceps muscle was especially small. The ratio of the quadriceps to all the thigh muscles in cross section was significantly smaller in affected side of hemiplegics than that of normal controls. This was observed even in normal side of the hemiplegics but the ratios of adductor and flexor muscles of the thigh showed no difference. Hypertrophy of gracilis muscle with high CT density was observed only on hemiplegic side. Muscle atrophies were marked in non-ambulatory patients. The ratios of quadriceps and saltorius muscles of thigh in non-ambulatory patients were significantly smaller than those of ambulatory patients. It could not be detected that there is relationship of the sevirity of the muscle atrophy and parietal lobe dysfunction. This atrophy considered to be the result of disuse of the paralyzed leg and pyramidal tract dysfunction. (author)

  6. Control of Leg Movements Driven by EMG Activity of Shoulder Muscles

    Science.gov (United States)

    La Scaleia, Valentina; Sylos-Labini, Francesca; Hoellinger, Thomas; Wang, Letian; Cheron, Guy; Lacquaniti, Francesco; Ivanenko, Yuri P.

    2014-01-01

    During human walking, there exists a functional neural coupling between arms and legs, and between cervical and lumbosacral pattern generators. Here, we present a novel approach for associating the electromyographic (EMG) activity from upper limb muscles with leg kinematics. Our methodology takes advantage of the high involvement of shoulder muscles in most locomotor-related movements and of the natural co-ordination between arms and legs. Nine healthy subjects were asked to walk at different constant and variable speeds (3–5 km/h), while EMG activity of shoulder (deltoid) muscles and the kinematics of walking were recorded. To ensure a high level of EMG activity in deltoid, the subjects performed slightly larger arm swinging than they usually do. The temporal structure of the burst-like EMG activity was used to predict the spatiotemporal kinematic pattern of the forthcoming step. A comparison of actual and predicted stride leg kinematics showed a high degree of correspondence (r > 0.9). This algorithm has been also implemented in pilot experiments for controlling avatar walking in a virtual reality setup and an exoskeleton during over-ground stepping. The proposed approach may have important implications for the design of human–machine interfaces and neuroprosthetic technologies such as those of assistive lower limb exoskeletons. PMID:25368569

  7. Classification system for flexor digitorum accessorius longus muscle variants within the leg: clinical correlations.

    Science.gov (United States)

    Hur, Mi-Sun; Won, Hyung-Sun; Oh, Chang-Seok; Chung, In-Hyuk; Lee, Woo-Chun; Yoon, Young Cheol

    2014-10-01

    The flexor digitorum accessorius longus (FDAL), a variant leg muscle, can cause tarsal tunnel syndrome. This study was performed to classify the variants of the FDAL by dissection and to correlate the dissection results with clinical cases of tarsal tunnel syndrome caused by this muscle. Eighty lower limbs of embalmed Korean cadavers were dissected. MR images of two clinical cases of tarsal tunnel syndrome caused by the FDAL were correlated with the dissection results. The FDAL was observed in nine out of 80 specimens (11.3%) and it was classified into three types depending on its site of origin and its relationship to the posterior tibial neurovascular bundle (PTNV) in the leg. In Type I (6.3%), the FDAL originated in the leg and ran superficially along the PTNV, either not crossing (Type Ia, 3.8%) or crossing (Type Ib, 2.5%) the neurovascular bundle. In Type II (6.3%), it originated in the tarsal tunnel. Most FDALs followed a similar course in the tarsal tunnel and the plantar pedis. On correlating the MR images of the clinical cases with this classification, the FDAL corresponded to Types Ia and II. All three types of FDAL can compress the tibial nerve in the tarsal tunnel or the distal leg. Clarification of the topographical relationship between this muscle and the PTNV would help to improve the results of surgery for tarsal tunnel syndrome caused by the FDAL. © 2014 Wiley Periodicals, Inc.

  8. Twins Bed Rest Project: LBNP/Exercise Minimizes Changes in Lean Leg Mass, Strength and Endurance

    Science.gov (United States)

    Amorim, Fabiano T.; Schneider, Suzanne M.; Lee, Stuart M. C.; Boda, Wanda L.; Watenpaugh, Donald E.; Hargens, Alan R.

    2006-01-01

    Decreases in muscle strength and endurance frequently are observed in non-weightbearing conditions such as bed rest (BR), spaceflight or limb immobilization. Purpose: Ow purpose was to determine if supine treadmill exercise against simulated gravity, by application of lower body negative pressure (LBNP), prevents loss of lean leg mass, strength and endurance during 30 d of 6deg head-down bed rest (BR). Methods: Fifteen pairs of monozygous twins (8 male, 7 female pairs; 26+/-4 yrs; 170+/-12 cm; 62.6+/-11.3 kg; mean+/-SD) were subjects in the present study. One sibling of each pair of twins was randomly assigned to either an exercise (EX) or non-exercise (CON) group. The EX twin walked/jogged on a vertical treadmill within LBNP chamber 6 d/wk using a 40-min interval exercise protocol at 40-80% of pre-BR VO(sub 2peak). LBNP was adjusted individually for each subject such that footward force was between 1.0 and 1.2 times body weight (-53+/-5 mmHg LBNP). The CON twin performed no exercise during BR. Subjects performed isokinetic knee (60 and 120deg/s) and ankle (60deg/s) testing to assess strength and endurance (End) before and after BR. They also had their lean leg mass (L(sub mass)) evaluated by DEXA before and after BR. Results: Changes in peak torque (T(sub pk)) were smaller for flexion (flex) than for extension (ext) after BR and did not differ between groups. The CON group had larger decreases (P<0.05) in L(sub mass), knee and ankle ext T(sub pk), and knee ext End.

  9. Signaling pathways controlling skeletal muscle mass

    Science.gov (United States)

    Egerman, Marc A.

    2014-01-01

    The molecular mechanisms underlying skeletal muscle maintenance involve interplay between multiple signaling pathways. Under normal physiological conditions, a network of interconnected signals serves to control and coordinate hypertrophic and atrophic messages, culminating in a delicate balance between muscle protein synthesis and proteolysis. Loss of skeletal muscle mass, termed “atrophy”, is a diagnostic feature of cachexia seen in settings of cancer, heart disease, chronic obstructive pulmonary disease, kidney disease, and burns. Cachexia increases the likelihood of death from these already serious diseases. Recent studies have further defined the pathways leading to gain and loss of skeletal muscle as well as the signaling events that induce differentiation and post-injury regeneration, which are also essential for the maintenance of skeletal muscle mass. In this review, we summarize and discuss the relevant recent literature demonstrating these previously undiscovered mediators governing anabolism and catabolism of skeletal muscle. PMID:24237131

  10. Anatomical description of the leg muscles of Procyon cancrivorus (Cuvier 1798

    Directory of Open Access Journals (Sweden)

    Firmino Cardoso Pereira

    2010-09-01

    Full Text Available The Procyon cancrivorus, as well as its entire family, is an endemic species of the Americas. It is widely found throughout the Brazilian territory and it inhabits all biomes, particularly the cerrado. This study used five adult specimens of P. cancrivorus for the characterization of the leg muscles. The animals were collected on roads (i. e. they had been killed by accident. The muscles were dissected, observing their proximal and distal insertions macroscopically, together with their topographic relationships to the arteries and nerves. The muscles studied are considered muscles of the tibia. The cranial tibial muscles, brevis, longus, long digital extensor and lateral extensor digitorum are craniolaterally distinct in the tibia, and the gastrocnemius muscles, lateral flexor of the fingers, popliteus, flexor digitorum, flexor digitorum and medial tibial flow are located in the caudal region of the tibia. The muscles of this group act as flexors and extensors of the hock joint and as flexors and extensors of the digital joints, except the popliteal muscle that acts as a flexor of the knee joint. The muscles studied were compared with their muscles in domestic carnivores, like the dog and cat, and great similarity was found.

  11. Altered lower leg muscle activation patterns in patients with cerebral palsy during cycling on an ergometer.

    Science.gov (United States)

    Alves-Pinto, Ana; Blumenstein, Tobias; Turova, Varvara; Lampe, Renée

    2016-01-01

    Cycling on a recumbent ergometer constitutes one of the most popular rehabilitation exercises in cerebral palsy (CP). However, no control is performed on how muscles are being used during training. Given that patients with CP present altered muscular activity patterns during cycling or walking, it is possible that an incorrect pattern of muscle activation is being promoted during rehabilitation cycling. This study investigated patterns of muscular activation during cycling on a recumbent ergometer in patients with CP and whether those patterns are determined by the degree of spasticity and of mobility. Electromyographic (EMG) recordings of lower leg muscle activation during cycling on a recumbent ergometer were performed in 14 adult patients diagnosed with CP and five adult healthy participants. EMG recordings were done with an eight-channel EMG system built in the laboratory. The activity of the following muscles was recorded: Musculus rectus femoris, Musculus biceps femoris, Musculus tibialis anterior, and Musculus gastrocnemius. The degree of muscle spasticity and mobility was assessed using the Modified Ashworth Scale and the Gross Motor Function Classification System, respectively. Muscle activation patterns were described in terms of onset and duration of activation as well as duration of cocontractions. Muscle activation in CP was characterized by earlier onsets, longer periods of activation, a higher occurrence of agonist-antagonist cocontractions, and a more variable cycling tempo in comparison to healthy participants. The degree of altered muscle activation pattern correlated significantly with the degree of spasticity. This study confirmed the occurrence of altered lower leg muscle activation patterns in patients with CP during cycling on a recumbent ergometer. There is a need to develop feedback systems that can inform patients and therapists of an incorrect muscle activation during cycling and support the training of a more physiological activation

  12. The effects of surface condition on abdominal muscle activity during single-legged hold exercise.

    Science.gov (United States)

    Ha, Sung-min; Oh, Jae-seop; Jeon, In-cheol; Kwon, Oh-yun

    2015-02-01

    To treat low-back pain, various spinal stability exercises are commonly used to improve trunk muscle function and strength. Because human movement for normal daily activity occurs in multi-dimensions, the importance of exercise in multi-dimensions or on unstable surfaces has been emphasized. Recently, a motorized rotating platform (MRP) for facilitating multi-dimensions dynamic movement was introduced for clinical use. However, the abdominal muscle activity with this device has not been reported. The purpose of this study was to compare the abdominal muscle activity (rectus abdominis, external and internal oblique muscles) during an active single-leg-hold (SLH) exercise on a floor (stable surface), foam roll, and motorized rotating platform (MRP). Thirteen healthy male subjects participated in this study. Using electromyography, the abdominal muscle activity was measured while the subjects performed SLH exercises on floor (stable surface), foam roll, and MRP. There were significant differences in the abdominal muscle activities among conditions (P.05) (Fig. 2). After the Bonferroni correction, however, no significant differences among conditions remained, except for differences in both side IO muscle activity between the floor and foam roll conditions (padjactivities of both side of RA and IO, and Rt. EO compared to floor condition. However, there were no significant differences in abdominal muscles activity in the multiple comparison between conditions (mean difference were smaller than the standard deviation in the abdominal muscle activities) (padj>0.017), except for differences in both side IO muscle activity between the floor (stable surface) and foam roll (padj<0.017) (effect size: 0.79/0.62 (non-supporting/supporting leg) for foam-roll versus floor). Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Experience with peroneus brevis muscle flaps for reconstruction of distal leg and ankle defects

    Directory of Open Access Journals (Sweden)

    Babu Bajantri

    2013-01-01

    Full Text Available Objective: Peroneus brevis is a muscle in the leg which is expendable without much functional deficit. The objective of this study was to find out its usefulness in coverage of the defects of the lower leg and ankle. Patients and Methods: A retrospective analysis of the use of 39 pedicled peroneus brevis muscle flaps used for coverage of defects of the lower leg and ankle between November 2010 and December 2012 was carried out. The flaps were proximally based for defects of the lower third of the leg in 12 patients and distally based for reconstruction of defects of the ankle in 26 patients, with one patient having flaps on both ankles. Results: Partial flap loss in critical areas was found in four patients requiring further flap cover and in non-critical areas in two patients, which were managed with a skin graft. Three of the four critical losses occurred when we used it for covering defects over the medial malleolus. There was no complete flap loss in any of the patients. Conclusion: This flap has a unique vascular pattern and fails to fit into the classification of the vasculature of muscles by Mathes and Nahai. The unusual feature is an axial vessel system running down the deep aspect of the muscle and linking the perforators from the peroneal artery and anterior tibial artery, which allows it to be raised proximally or distally on a single perforator. The flap is simple to raise and safe for the reconstruction of small-to moderate-sized skin defects of the distal third of the tibia and all parts of the ankle except the medial malleolus, which is too far from the pedicle of the distally based flap. The donor site can be closed primarily to provide a linear scar. The muscle flap thins with time to provide a good result aesthetically at the primary defect.

  14. Quantitation of progressive muscle fatigue during dynamic leg exercise in humans

    DEFF Research Database (Denmark)

    Fulco, C S; Lewis, S F; Frykman, Peter

    1995-01-01

    There is virtually no published information on muscle fatigue, defined as a gradual decline in force-generating capacity, during conventional dynamic (D) leg exercise. To quantitate progression of fatigue, we developed 1) a model featuring integration of maximal voluntary static contraction (MVC.......05) for matched DKE work rates. To track fatigue, MVC (90 degrees knee angle) was performed every 2 min of DKE. After 4 min of DKE at work rates corresponding to (mean +/- SE) 66 +/- 2, 78 +/- 2, and 100% of peak DKE O2 uptake, MVC fell to 95 +/- 3, 90 +/- 5, and 65 +/- 7%* of MVC of rested muscle, respectively...... (*P fatigue during D leg exercise provides a framework to study the effects of a variety...

  15. Effect of Locomotor Training on Exhaustion of Leg Muscle Activity in Chronic Complete Spinal Cord Injury.

    Science.gov (United States)

    Schrafl-Altermatt, Miriam; Dietz, Volker; Bolliger, Marc

    2017-08-01

    The aim of this study was to evaluate the effect of a continuous locomotor training on leg muscle electromyographic (EMG) exhaustion during assisted stepping movements in a patient with motor complete spinal cord injury (SCI). EMG exhaustion and loss of potentials starts to develop in untrained patients at ∼6 months after injury. In the trained patient examined in this study, exhaustion was also observed but occurred with a delay of several months. In contrast to an untrained patient, no more EMG exhaustion was observed in the very chronic stage. At this time (12 years after injury) a basic locomotor pattern of leg muscle activity of reduced amplitude could still be elicited, but it was resistant to exhaustion and unchanged in amplitude after 12 min of assisted stepping. It is suggested that fatigue-resistant motor units prevail at this stage and can still be activated during stepping as a result of the training.

  16. Lower leg muscle involvement in Duchenne muscular dystrophy: an MR imaging and spectroscopy study

    Energy Technology Data Exchange (ETDEWEB)

    Torriani, Martin [Massachusetts General Hospital and Harvard Medical School, Division of Musculoskeletal Imaging and Intervention, Boston, MA (United States); Massachusetts General Hospital, Musculoskeletal Imaging and Intervention, Department of Radiology, Boston, MA (United States); Townsend, Elise [MGH Institute of Health Professions and Massachusetts General Hospital, Boston, MA (United States); Thomas, Bijoy J.; Bredella, Miriam A.; Ghomi, Reza H. [Massachusetts General Hospital and Harvard Medical School, Division of Musculoskeletal Imaging and Intervention, Boston, MA (United States); Tseng, Brian S. [Massachusetts General Hospital and Harvard Medical School, Pediatric Neuromuscular Clinic, Boston, MA (United States); Novartis Institute of Biomedical Research, Cambridge, MA (United States)

    2012-04-15

    To describe the involvement of lower leg muscles in boys with Duchenne muscular dystrophy (DMD) by using MR imaging (MRI) and spectroscopy (MRS) correlated to indices of functional status. Nine boys with DMD (mean age, 11 years) and eight healthy age- and BMI-matched boys (mean age, 13 years) prospectively underwent lower leg MRI, 1H-MRS of tibialis anterior (TA) and soleus (SOL) for lipid fraction measures, and 31P-MRS for pH and high-energy phosphate measures. DMD subjects were evaluated using the Vignos lower extremity functional rating, and tests including 6 min walk test (6MWT) and 10 m walk. DMD subjects had highest fatty infiltration scores in peroneal muscles, followed by medial gastrocnemius and soleus. Compared to controls, DMD boys showed higher intramuscular fat (P = 0.04), lipid fractions of TA and SOL (P = 0.02 and 0.003, respectively), pH of anterior compartment (P = 0.0003), and lower phosphocreatine/inorganic phosphorus ratio of posterior compartment (P = 0.02). The Vignos rating correlated with TA (r = 0.79, P = 0.01) and SOL (r = 0.71, P = 0.03) lipid fractions. The 6MWT correlated with fatty infiltration scores of SOL (r = -0.76, P = 0.046), medial (r = -0.80, P = 0.03) and lateral (r = -0.84, P = 0.02) gastrocnemius, intramuscular fat (r = -0.80, P = 0.03), and SOL lipid fraction (r = -0.89, P = 0.007). Time to walk 10 m correlated with anterior compartment pH (r = 0.78, P = 0.04). Lower leg muscles of boys with DMD show a distinct involvement pattern and increased adiposity that correlates with functional status. Lower leg MRI and 1H-MRS studies may help to noninvasively demonstrate the severity of muscle involvement. (orig.)

  17. Lower leg muscle involvement in Duchenne muscular dystrophy: an MR imaging and spectroscopy study

    International Nuclear Information System (INIS)

    Torriani, Martin; Townsend, Elise; Thomas, Bijoy J.; Bredella, Miriam A.; Ghomi, Reza H.; Tseng, Brian S.

    2012-01-01

    To describe the involvement of lower leg muscles in boys with Duchenne muscular dystrophy (DMD) by using MR imaging (MRI) and spectroscopy (MRS) correlated to indices of functional status. Nine boys with DMD (mean age, 11 years) and eight healthy age- and BMI-matched boys (mean age, 13 years) prospectively underwent lower leg MRI, 1H-MRS of tibialis anterior (TA) and soleus (SOL) for lipid fraction measures, and 31P-MRS for pH and high-energy phosphate measures. DMD subjects were evaluated using the Vignos lower extremity functional rating, and tests including 6 min walk test (6MWT) and 10 m walk. DMD subjects had highest fatty infiltration scores in peroneal muscles, followed by medial gastrocnemius and soleus. Compared to controls, DMD boys showed higher intramuscular fat (P = 0.04), lipid fractions of TA and SOL (P = 0.02 and 0.003, respectively), pH of anterior compartment (P = 0.0003), and lower phosphocreatine/inorganic phosphorus ratio of posterior compartment (P = 0.02). The Vignos rating correlated with TA (r = 0.79, P = 0.01) and SOL (r = 0.71, P = 0.03) lipid fractions. The 6MWT correlated with fatty infiltration scores of SOL (r = -0.76, P = 0.046), medial (r = -0.80, P = 0.03) and lateral (r = -0.84, P = 0.02) gastrocnemius, intramuscular fat (r = -0.80, P = 0.03), and SOL lipid fraction (r = -0.89, P = 0.007). Time to walk 10 m correlated with anterior compartment pH (r = 0.78, P = 0.04). Lower leg muscles of boys with DMD show a distinct involvement pattern and increased adiposity that correlates with functional status. Lower leg MRI and 1H-MRS studies may help to noninvasively demonstrate the severity of muscle involvement. (orig.)

  18. Relationships among serum testosterone levels, body fat and muscle mass distribution in women with polycystic ovary syndrome.

    Science.gov (United States)

    Douchi, T; Yoshimitsu, N; Nagata, Y

    2001-12-01

    We investigated the relationships among serum testosterone levels, body fat and muscle mass distribution in women with polycystic ovary syndrome (PCOS). Subjects were 67 women with PCOS (mean age +/- standard deviation, 28.8 +/- 6.6 years). Baseline characteristics included age and height. Trunk-leg fat ratio and trunk-leg muscle ratio were assessed with dual-energy x-ray absorptiometry. Serum testosterone and dehydroepiandrosterone sulfate levels were measured with radioimmunoassays. Relationships among serum testosterone levels, body fat and muscle mass distribution were investigated using Pearson and partial correlation tests. Serum testosterone levels were positively correlated with trunk-leg fat ratio (r = 0.398, P fat ratio (r = -0.360, P testosterone levels were still correlated with trunk-leg fat ratio (r = 0.500, P fat ratio was still correlated with trunk-leg muscle ratio, after adjusting for age, height, and serum testosterone levels. Based on these results, we concluded that higher serum testosterone levels may contribute to the upper body fat distribution and peripheral muscle mass distribution. In addition, peripheral muscle mass distribution may also contribute to the upper body fat distribution.

  19. CT findings of leg muscles in the hemiplegics due to cerebrovascular accidents

    International Nuclear Information System (INIS)

    Odajima, Natsu; Ishiai, Sumio; Okiyama, Ryouichi; Furukawa, Tetsuo; Tsukagoshi, Hiroshi.

    1987-01-01

    Muscle wastings in hemiplegics due to cerebrovascular accidents were studied with CT scanning in the mid-portion of the thigh and largest-diameter section of the calf bilaterally. Muscle size and average CT density of muscle were measured. The 80 patients were classified into one of the following three stages of disability, i.e. stage 1, severely disabled (wheel-chair-bound but capable of self care [20 patients]); stage 2, moderately disabled (poorly ambulatory [41 patients]); and stage 3, mildly disabled (well ambulatory [19 patients]). Muscle cross-sectional area and CT density in both legs of non-ambulatory patients were smaller and lower than those of other groups. The atrophic change was marked in the affected side, but it was also noticeable in the non-affected side. Gracilis muscle was relatively well spared in all 3 stages. These CT findings of hemiplegics were similar to those of disuse atropy in patients with knee or hip joint lesions. Atrophy was seen first in the quadriceps in thigh and flexor muscle group in calf. These findings were similar to the systemic myogenic or neurogenic atrophies. Although gracilis and sartorius muscles were spared in these systemic deseases, only gracilis muscle was spared in hemiplegics and in patients with disuse atrophy. The ratios of the size of quadriceps, adductor group and sartorius muscle of thigh in affected side to that of non-affected side were smaller in more severely disabled group. Those of the other muscles showed no differences among each stages. In stage 3, there was significant negative correlation between the ratio of quadriceps muscle and periods from the attack. There was no relationship between the severity of the muscle atrophy and parietal lobe lesion. The atrophy is considered to be the result of disuse from immobilization. (author)

  20. Changes in serum creatine kinase, leg muscle tightness, and delayed onset muscle soreness after a full marathon race.

    Science.gov (United States)

    Tojima, Michio; Noma, Kensuke; Torii, Suguru

    2016-06-01

    Muscle tightness (MT) is believed to be an important cause of injury for runners. This study evaluated the change of serum creatine kinase (CK), MT in the leg muscles, and delayed onset muscle soreness after running. We evaluated 11 college students who completed a full marathon race. Participants completed a questionnaire on the right quadriceps muscle soreness. The CK activity and MT (iliopsoas, rectus femoris, hamstrings, gastrocnemius, and soleus muscles) were measured. The time points for CK measurements were before; immediately after; and at 1, 2, and 5 days after the race. The time points for MT measurements were the same as for CK except MT was not measured one day after the race. The time points for muscle soreness analysis were before the race and then every morning and night for 5 days after the race. Long-distance running led to significant increases in CK, MT, and muscle soreness. The CK levels peaked day 1 after the race. MT of iliopsoas peaked on day 5; of rectus femoris immediately after the race; and of hamstrings, gastrocnemius, and soleus on day 2. muscle soreness peaked at night on day 1. MT did not decrease to the pre-race levels on day 5. There were no significant changes but CK tended to correlate with the peak of MT of the rectus femoris (r=0.55, P=0.082) and hamstrings (r=0.57, P=0.065). Long-distance running may cause muscle fiber microdamage that may consequently increase CK, MT, and muscle soreness.

  1. Influence of unstable footwear on lower leg muscle activity, volume change and subjective discomfort during prolonged standing.

    Science.gov (United States)

    Karimi, Zanyar; Allahyari, Teimour; Azghani, Mahmood Reza; Khalkhali, Hamidreza

    2016-03-01

    The present study was an attempt to investigate the effect of unstable footwear on lower leg muscle activity, volume change and subjective discomfort during prolonged standing. Ten healthy subjects were recruited to stand for 2 h in three footwear conditions: barefoot, flat-bottomed shoe and unstable shoe. During standing, lower leg discomfort and EMG activity of medial gastrocnemius (MG) and tibialis anterior (TA) muscles were continuously monitored. Changes in lower leg volume over standing time also were measured. Lower leg discomfort rating reduced significantly while subjects standing on unstable shoe compared to the flat-bottomed shoe and barefoot condition. For lower leg volume, less changes also were observed with unstable shoe. The activity level and variation of right MG muscle was greater with unstable shoe compared to the other footwear conditions; however regarding the left MG muscle, significant difference was found between unstable shoe and flat-bottomed shoe only for activity level. Furthermore no significant differences were observed for the activity level and variation of TA muscles (right/left) among all footwear conditions. The findings suggested that prolonged standing with unstable footwear produces changes in lower leg muscles activity and leads to less volume changes. Perceived discomfort also was lower for this type of footwear and this might mean that unstable footwear can be used as ergonomic solution for employees whose work requires prolonged standing. Copyright © 2015 Elsevier Ltd and The Ergonomics Society. All rights reserved.

  2. Night Leg Cramps

    Science.gov (United States)

    Symptoms Night leg cramps By Mayo Clinic Staff Night leg cramps, also called nocturnal leg cramps, are painful, involuntary contractions or spasms of muscles in your legs, usually occurring when you're in bed. Night ...

  3. Mechanical Impedance of the non-loaded Lower Leg with Relaxed Muscles in the Transverse Plane

    Directory of Open Access Journals (Sweden)

    Evandro Maicon Ficanha

    2015-12-01

    Full Text Available This paper describes the protocols and results of the experiments for the estimation of the mechanical impedance of the humans’ lower leg in the External-Internal (EI direction in the transverse plane under non-load bearing condition and with relaxed muscles. The objectives of the estimation of the lower leg’s mechanical impedance are to facilitate the design of passive and active prostheses with mechanical characteristics similar to the humans’ lower leg, and to define a reference that can be compared to the values from the patients suffering from spasticity. The experiments were performed with 10 unimpaired male subjects using a lower extremity rehabilitation robot (Anklebot, Interactive Motion Technologies, Inc. capable of applying torque perturbations to the foot. The subjects were in a seated position, and the Anklebot recorded the applied torques and the resulting angular movement of the lower leg. In this configuration, the recorded dynamics are due mainly to the rotations of the ankle’s talocrural and the subtalar joints, and any contribution of the tibiofibular joints and knee joint. The dynamic mechanical impedance of the lower leg was estimated in the frequency domain with an average coherence of 0.92 within the frequency range of 0 to 30Hz, showing a linear correlation between the displacement and the torques within this frequency range under the conditions of the experiment. The mean magnitude of the quasi-static stiffness of the lower leg (the impedance magnitude averaged in the range of 0-1 Hz was determined as 4.9±0.74 Nm/rad. The direct estimation of the quasi-static stiffness of the lower leg results in the mean value of 5.8±0.81 Nm/rad. An analysis of variance (ANOVA shows that the estimated values for the quasi-static stiffness from the two experiments are not statistically different.

  4. Features interference EMG leg extensor muscles of skilled players in the context of the special exercises

    Directory of Open Access Journals (Sweden)

    Sirenko P.A.

    2013-06-01

    Full Text Available The article considers the problems of improvement of physical training of skilled players. The main instrumental method of the research is electromyography. The aim of the research is determination of the optimal angle of the provisions of legs on her hips for the appearance of a maximum of bioelectric activity of the muscles of the front panel hips in exercise unbending legs sitting on the mechanical simulator. In the course of research we have worked for electromyography 10 players of FC Metalist at the age of 19 – 30 years during the five-second of the submaximum contraction of these muscles as: musculus rectus femoris, musculus vastus medialis, musculus vastus lateralis. The results of the analysis of segments of electromyography allowed to make a conclusion, that we investigated the provisions of the angle of 140 degrees has the lowest preconditions for the appearance of muscle strength. We have obtained data testify to the fact that the angle of 90 degrees is the position of the greatest preconditions for the appearance of muscle strength.

  5. Sarcopenia and Predictors of Skeletal Muscle Mass in Elderly Men With and Without Obesity

    Directory of Open Access Journals (Sweden)

    Katja Stoever MA

    2017-06-01

    Full Text Available Objectives: The aim of this study was to determine the variables which show the highest association with muscle mass and to identify the most important predictors for muscle mass in elderly men with and without sarcopenia. Methods: A total of 71 men participated, aged ≥65 years. Sarcopenia was assessed using the definition of the European Working Group on Sarcopenia in Older People with determining skeletal muscle index (SMI, hand-grip strength (HGS, and Short Physical Performance Battery. In addition, maximum strength at upper and lower extremities and physical activity were measured. Results: Strong correlations existed between SMI and gait speed, HGS, maximum isometric strength at leg and chest press. Physical activity showed low correlations with muscle strength. Regression analysis revealed HGS and gait speed as key predictors for SMI. Discussion: The recommendation is measuring gait speed and HGS in clinical practice at first followed by measuring muscle mass for determining sarcopenia.

  6. An analysis methodology for hot leg break mass and energy release

    International Nuclear Information System (INIS)

    Song, Jin Ho; Kwon, Young Min; Kim, Taek Mo; Chung, Hae Yong; Lee, Sang Jong

    1996-07-01

    An analysis methodology for the hot leg break mass and energy release is developed. For the blowdown period a modified CEFLASH-4A analysis is suggested. For the post-blowdown period a new computer model named COMET is developed. Differently from previous post-blowdown analysis model FLOOD3, COMET is capable of analyzing both cold leg and hot leg break cases. The cold leg break model is essentially same as that of FLOOD3 with some improvements. The analysis results by the newly proposed hot leg break model in the COMET is in the same trend as those observed in scaled-down integral experiment. And the analyses results for the UCN 3 and 4 by COMET are qualitatively and quantitatively in good agreement with those predicted by best-estimate analysis by using RELAP5/MOD3. Therefore, the COMET code is validated and can be used for the licensing analysis. 6 tabs., 82 figs., 9 refs. (Author)

  7. Myosin heavy-chain isoforms in the flight and leg muscles of hummingbirds and zebra finches.

    Science.gov (United States)

    Velten, Brandy P; Welch, Kenneth C

    2014-06-01

    Myosin heavy chain (MHC) isoform complement is intimately related to a muscle's contractile properties, yet relatively little is known about avian MHC isoforms or how they may vary with fiber type and/or the contractile properties of a muscle. The rapid shortening of muscles necessary to power flight at the high wingbeat frequencies of ruby-throated hummingbirds and zebra finches (25-60 Hz), along with the varied morphology and use of the hummingbird hindlimb, provides a unique opportunity to understand how contractile and morphological properties of avian muscle may be reflected in MHC expression. Isoforms of the hummingbird and zebra finch flight and hindlimb muscles were electrophoretically separated and compared with those of other avian species representing different contractile properties and fiber types. The flight muscles of the study species operate at drastically different contraction rates and are composed of different histochemically defined fiber types, yet each exhibited the same, single MHC isoform corresponding to the chicken adult fast isoform. Thus, despite quantitative differences in the contractile demands of flight muscles across species, this isoform appears necessary for meeting the performance demands of avian powered flight. Variation in flight muscle contractile performance across species may be due to differences in the structural composition of this conserved isoform and/or variation within other mechanically linked proteins. The leg muscles were more varied in their MHC isoform composition across both muscles and species. The disparity in hindlimb MHC expression between hummingbirds and the other species highlights previously observed differences in fiber type composition and thrust production during take-off. Copyright © 2014 the American Physiological Society.

  8. Net joint moments and muscle activation in barbell squats without and with restricted anterior leg rotation.

    Science.gov (United States)

    Chiu, Loren Z F; vonGaza, Gabriella L; Jean, Liane M Y

    2017-01-01

    Muscle utilisation in squat exercise depends on technique. The purpose of this study was to compare net joint moments (NJMs) and muscle activation during squats without and with restricted leg dorsiflexion. Experienced men (n = 5) and women (n = 4) performed full squats at 80% one repetition maximum. 3D motion analysis, force platform and (EMG) data were collected. Restricting anterior leg rotation reduced anterior leg (P = 0.001) and posterior thigh (P  0.05), vastus medialis (P > 0.05) and rectus femoris (P > 0.05) EMG were not different between squat types. Unrestricted squats have higher ankle plantar flexor and knee extensor NJM than previously reported from jumping and landing. However, ankle plantar flexor and knee extensor NJM are lower in restricted squats than previous studies of jumping and landing. The high NJM in unrestricted squat exercise performed through a full range of motion suggests this squat type would be more effective to stimulate adaptations in the lower extremity musculature than restricted squats.

  9. Anthropometric parameters as predictors of muscle mass in elderly women

    Directory of Open Access Journals (Sweden)

    Fábio da Silva Santana

    2015-08-01

    Full Text Available The aims of study were to analyze the relationship between muscle mass and anthropometric parameters in elderly women and to develop a mathematical model to predict muscle mass based on anthropometric parameters. The study included 63 elderly women (71.4 ± 4.4 years. Body weight, height, arm, waist, hip and calf circumferences were measured. Muscle mass was estimated using a densitometry. The muscle mass index was calculated using the equation (muscle mass index = muscle mass [kg] / height [m]². A significant correlation was found between muscle mass and body weight (r = 0.782, arm (r=0.688, waist (r=0.467, hip (r=0.629 and calf circumferences (r=0.592 with p<0.05 for all. Regression analysis indicated that body mass and calf circumference were independent predictors of muscle mass (r=0.81, r²=0.65, F=55.7. The prediction model obtained was muscle mass (kg=-0.543+(0.162*body mass+(0.151*calf circumference. No differences were observed between the amount of muscle mass and muscle mass index estimated by densitometry and by equation (p>0.05. The results of this study indicated that body mass, body mass index, arm, waist, hip and calf circumferences are related to muscle mass elderly women. The muscle mass can be adequately predicted based on data from body mass and calf circumference.

  10. A common neural element receiving rhythmic arm and leg activity as assessed by reflex modulation in arm muscles.

    Science.gov (United States)

    Sasada, Syusaku; Tazoe, Toshiki; Nakajima, Tsuyoshi; Futatsubashi, Genki; Ohtsuka, Hiroyuki; Suzuki, Shinya; Zehr, E Paul; Komiyama, Tomoyoshi

    2016-04-01

    Neural interactions between regulatory systems for rhythmic arm and leg movements are an intriguing issue in locomotor neuroscience. Amplitudes of early latency cutaneous reflexes (ELCRs) in stationary arm muscles are modulated during rhythmic leg or arm cycling but not during limb positioning or voluntary contraction. This suggests that interneurons mediating ELCRs to arm muscles integrate outputs from neural systems controlling rhythmic limb movements. Alternatively, outputs could be integrated at the motoneuron and/or supraspinal levels. We examined whether a separate effect on the ELCR pathways and cortico-motoneuronal excitability during arm and leg cycling is integrated by neural elements common to the lumbo-sacral and cervical spinal cord. The subjects performed bilateral leg cycling (LEG), contralateral arm cycling (ARM), and simultaneous contralateral arm and bilateral leg cycling (A&L), while ELCRs in the wrist flexor and shoulder flexor muscles were evoked by superficial radial (SR) nerve stimulation. ELCR amplitudes were facilitated by cycling tasks and were larger during A&L than during ARM and LEG. A low stimulus intensity during ARM or LEG generated a larger ELCR during A&L than the sum of ELCRs during ARM and LEG. We confirmed this nonlinear increase in single motor unit firing probability following SR nerve stimulation during A&L. Furthermore, motor-evoked potentials following transcranial magnetic and electrical stimulation did not show nonlinear potentiation during A&L. These findings suggest the existence of a common neural element of the ELCR reflex pathway that is active only during rhythmic arm and leg movement and receives convergent input from contralateral arms and legs. Copyright © 2016 the American Physiological Society.

  11. Altered lower leg muscle activation patterns in patients with cerebral palsy during cycling on an ergometer

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    Alves-Pinto A

    2016-06-01

    Full Text Available Ana Alves-Pinto,1,* Tobias Blumenstein,1,* Varvara Turova,1 Renée Lampe1,2 1Research Unit of the Buhl-Strohmaier Foundation for Cerebral Palsy and Paediatric Neuroorthopaedics, Orthopaedic Department, Klinikum rechts der Isar, 2Markus Würth Professorship, Technical University of Munich, Munich, Germany *These authors contributed equally to this work Objective: Cycling on a recumbent ergometer constitutes one of the most popular rehabilitation exercises in cerebral palsy (CP. However, no control is performed on how muscles are being used during training. Given that patients with CP present altered muscular activity patterns during cycling or walking, it is possible that an incorrect pattern of muscle activation is being promoted during rehabilitation cycling. This study investigated patterns of muscular activation during cycling on a recumbent ergometer in patients with CP and whether those patterns are determined by the degree of spasticity and of mobility.Methods: Electromyographic (EMG recordings of lower leg muscle activation during cycling on a recumbent ergometer were performed in 14 adult patients diagnosed with CP and five adult healthy participants. EMG recordings were done with an eight-channel EMG system built in the laboratory. The activity of the following muscles was recorded: Musculus rectus femoris, Musculus biceps femoris, Musculus tibialis anterior, and Musculus gastrocnemius. The degree of muscle spasticity and mobility was assessed using the Modified Ashworth Scale and the Gross Motor Function Classification System, respectively. Muscle activation patterns were described in terms of onset and duration of activation as well as duration of cocontractions.Results: Muscle activation in CP was characterized by earlier onsets, longer periods of activation, a higher occurrence of agonist–antagonist cocontractions, and a more variable cycling tempo in comparison to healthy participants. The degree of altered muscle activation

  12. The Effect of Kick Type on the Relationship between Kicking Leg Muscle Activation and Ball Velocity

    Directory of Open Access Journals (Sweden)

    Ali Onur Cerrah

    2018-03-01

    Full Text Available This study aimed to identify the effects of different kick types on the relationship between kicking leg muscle activation and ball velocity. The muscle activation of selected knee extensor and flexor muscles of 10 amateur soccer players were measured using electromyography during the performance of six maximal soccer kick types. The highest ball velocity was achieved by the instep kick (96.2 km/hr-1, followed by the lofted kick, the inside curve kick, the outside kick, the outside curve kick, and finally the inside kick (81.3 km/hr-1. There were significant positive correlations between muscle activation and ball velocity for the vastus lateralis and lofted (0.765, inside curve (0.792 and instep kicks (0.788, and for the gastrocnemious with the outside kick (0.796. Non-significant correlations between muscle activation and ball velocity exhibited a trend such that they were positive for the vastus medialis and vastus lateralis but negative for the biceps femoris and gastrocnemious for inside-foot-dominated kicks, while this trend was reversed for outside-foot-dominated kicks. According to results, the noted trends can be explained by the change in muscle activation patterns required to orientate the foot for each type of kick; this has implications for players’ training activities.

  13. EFFECT OF MODERATE ALTITUDE ON PERIPHERAL MUSCLE OXYGENATION DURING LEG RESISTANCE EXERCISE IN YOUNG MALES

    Directory of Open Access Journals (Sweden)

    Toshio Matsuoka

    2004-09-01

    Full Text Available Training at moderate altitude (~1800m is often used by athletes to stimulate muscle hypoxia. However, limited date is available on peripheral muscle oxidative metabolism at this altitude (1800AL. The purpose of this study was to determine whether acute exposure to 1800AL alters muscle oxygenation in the vastus lateralis muscle during resistance exercise. Twenty young active male subjects (aged 16 - 21 yr performed up to 50 repetitions of the parallel squat at 1800AL and near sea level (SL. They performed the exercise protocol within 3 h after arrival at 1800 AL. During the exercise, the changes in oxygenated hemoglobin (OxyHb in the vastus lateralis muscle, arterial oxygen saturation (SpO2, and heart rate were measured using near infrared continuous wave spectroscopy (NIRcws and pulse oximetry, respectively. Changes in OxyHb were expressed by Deff defined as the relative index of the maximum change ratio (% from the resting level. OxyHb in the vastus lateralis muscle decreased dramatically from the resting level immediately after the start of exercise at both altitudes. The Deff during exercise was significantly (p < 0.001 lower at 1800AL (60.4 ± 6.2 % than at near SL (74.4 ± 7.6 %. SpO2 during exercise was significantly (p < 0.001 lower at 1800AL (92.0 ± 1.7 % than at near SL (96.7 ± 1.2 %. Differences (SL - 1800AL in Deff during exercise correlated fairly strongly with differences in SpO2 during exercise (r = 0.660. These results suggested that acute exposure to moderate altitude caused a more dramatical decrease in peripheral muscle oxygenation during leg resistance exercise. It is salient to note, therefore , that peripheral muscle oxygenation status at moderate altitude could be evaluated using NIRcws and that moderate altitudes might be effectively used to apply hypoxic stress on peripheral muscles.

  14. Assessment of nutritional status in adult patients with cystic fibrosis: whole-body bioimpedance vs body mass index, skinfolds, and leg-to-leg bioimpedance

    NARCIS (Netherlands)

    Hollander, F.M.; Roos, de N.M.; Vries, de J.H.M.; Berkhout, van F.T.

    2005-01-01

    Objective: To investigate whether body mass index (BMI) or body fat percentage estimated from BMI, skinfolds, or leg-to-leg bioimpedance are good indicators of nutritional status in adult patients with cystic fibrosis. Body fat percentage measured by whole-body bioimpedance was used as the reference

  15. Age-related changes in the effects of strength training on lower leg muscles in healthy individuals measured using MRI

    OpenAIRE

    Psatha, Maria; Wu, Zhiqing; Gammie, Fiona; Ratkevicius, Aivaras; Wackerhage, Henning; Redpath, Thomas W; Gilbert, Fiona J; Meakin, Judith R; Aspden, Richard M

    2017-01-01

    Background We previously measured the rate of regaining muscle strength during rehabilitation of lower leg muscles in patients following lower leg casting. Our primary aim in this study was to measure the rate of gain of strength in healthy individuals undergoing a similar training regime. Our secondary aim was to test the ability of MRI to provide a biomarker for muscle function. Methods Men and women were recruited in three age groups: 20?30, 50?65 and over 70 years. Their response to resis...

  16. Reliability of a Novel High Intensity One Leg Dynamic Exercise Protocol to Measure Muscle Endurance.

    Directory of Open Access Journals (Sweden)

    Benjamin Pageaux

    Full Text Available We recently developed a high intensity one leg dynamic exercise (OLDE protocol to measure muscle endurance and investigate the central and peripheral mechanisms of muscle fatigue. The aims of the present study were to establish the reliability of this novel protocol and describe the isokinetic muscle fatigue induced by high intensity OLDE and its recovery. Eight subjects performed the OLDE protocol (time to exhaustion test of the right leg at 85% of peak power output three times over a week period. Isokinetic maximal voluntary contraction torque at 60 (MVC60, 100 (MVC100 and 140 (MVC140 deg/s was measured pre-exercise, shortly after exhaustion (13 ± 4 s, 20 s (P20 and 40 s (P40 post-exercise. Electromyographic (EMG signal was analyzed via the root mean square (RMS for all three superficial knee extensors. Mean time to exhaustion was 5.96 ± 1.40 min, coefficient of variation was 8.42 ± 6.24%, typical error of measurement was 0.30 min and intraclass correlation was 0.795. MVC torque decreased shortly after exhaustion for all angular velocities (all P < 0.001. MVC60 and MVC100 recovered between P20 (P < 0.05 and exhaustion and then plateaued. MVC140 recovered only at P40 (P < 0.05. High intensity OLDE did not alter maximal EMG RMS of the three superficial knee extensors during MVC. The results of this study demonstrate that this novel high intensity OLDE protocol could be reliably used to measure muscle endurance, and that muscle fatigue induced by high intensity OLDE should be examined within ~ 30 s following exhaustion.

  17. Alterations in Leg Extensor Muscle-Tendon Unit Biomechanical Properties With Ageing and Mechanical Loading

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    Christopher McCrum

    2018-02-01

    Full Text Available Tendons transfer forces produced by muscle to the skeletal system and can therefore have a large influence on movement effectiveness and safety. Tendons are mechanosensitive, meaning that they adapt their material, morphological and hence their mechanical properties in response to mechanical loading. Therefore, unloading due to immobilization or inactivity could lead to changes in tendon mechanical properties. Additionally, ageing may influence tendon biomechanical properties directly, as a result of biological changes in the tendon, and indirectly, due to reduced muscle strength and physical activity. This review aimed to examine age-related differences in human leg extensor (triceps surae and quadriceps femoris muscle-tendon unit biomechanical properties. Additionally, this review aimed to assess if, and to what extent mechanical loading interventions could counteract these changes in older adults. There appear to be consistent reductions in human triceps surae and quadriceps femoris muscle strength, accompanied by similar reductions in tendon stiffness and elastic modulus with ageing, whereas the effect on tendon cross sectional area is unclear. Therefore, the observed age-related changes in tendon stiffness are predominantly due to changes in tendon material rather than size with age. However, human tendons appear to retain their mechanosensitivity with age, as intervention studies report alterations in tendon biomechanical properties in older adults of similar magnitudes to younger adults over 12–14 weeks of training. Interventions should implement tendon strains corresponding to high mechanical loads (i.e., 80–90% MVC with repetitive loading for up to 3–4 months to successfully counteract age-related changes in leg extensor muscle-tendon unit biomechanical properties.

  18. Ankle muscle activity modulation during single-leg stance differs between children, young adults and seniors.

    Science.gov (United States)

    Kurz, Eduard; Faude, Oliver; Roth, Ralf; Zahner, Lukas; Donath, Lars

    2018-02-01

    Incomplete maturation and aging-induced declines of the neuromuscular system affect postural control both in children and older adults and lead to high fall rates. Age-specific comparisons of the modulation of ankle muscle activation and behavioral center of pressure (COP) indices during upright stance have been rarely conducted. The objective of the present study was to quantify aging effects on a neuromuscular level. Thus, surface electromyography (SEMG) modulation and co-activity of ankle muscles during single-leg standing was compared in healthy children, young adults and seniors. Postural steadiness (velocity and mean sway frequency of COP), relative muscle activation (SEMG modulation) and co-activation of two ankle muscles (tibialis anterior, TA; soleus, SO) were examined during single-leg stance in 19 children [age, 9.7 (SD 0.5) years], 30 adults [23.3 (1.5) years] and 29 seniors [62.7 (6.1) years]. Velocity of COP in medio-lateral and anterior-posterior directions, mean sway frequency in anterior-posterior direction, relative muscle activation (TA and SO) and co-activation revealed large age effects (P  0.14). Post-hoc comparisons indicated higher COP velocities, anterior-posterior frequencies, relative SO activation and co-activation in children and seniors when compared with adults. Relative TA activation was higher in children and adults compared with seniors (P modulation. However, TA modulation is higher in children and adults, whereas seniors' TA modulation capacity is diminished. An aging-induced decline of TA motor units might account for deteriorations of TA modulation in seniors.

  19. Intermittent pneumatic leg compressions acutely upregulate VEGF and MCP-1 expression in skeletal muscle.

    Science.gov (United States)

    Roseguini, Bruno T; Mehmet Soylu, S; Whyte, Jeffrey J; Yang, H T; Newcomer, Sean; Laughlin, M Harold

    2010-06-01

    Application of intermittent pneumatic compressions (IPC) is an extensively used therapeutic strategy in vascular medicine, but the mechanisms by which this method works are unclear. We tested the hypothesis that acute application (150 min) of cyclic leg compressions in a rat model signals upregulation of angiogenic factors in skeletal muscle. To explore the impact of different pressures and frequency of compressions, we divided rats into four groups as follows: 120 mmHg (2 s inflation/2 s deflation), 200 mmHg (2 s/2 s), 120 mmHg (4 s/16 s), and control (no intervention). Blood flow and leg oxygenation (study 1) and the mRNA expression of angiogenic mediators in the rat tibialis anterior muscle (study 2) were assessed after a single session of IPC. In all three groups exposed to the intervention, a modest hyperemia (approximately 37% above baseline) between compressions and a slight, nonsignificant increase in leg oxygen consumption (approximately 30%) were observed during IPC. Compared with values in the control group, vascular endothelial growth factor (VEGF) and monocyte chemotactic protein-1 (MCP-1) mRNA increased significantly (P < 0.05) only in rats exposed to the higher frequency of compressions (2 s on/2 s off). Endothelial nitric oxide synthase, matrix metalloproteinase-2, and hypoxia-inducible factor-1alpha mRNA did not change significantly following the intervention. These findings show that IPC application augments the mRNA content of key angiogenic factors in skeletal muscle. Importantly, the magnitude of changes in mRNA expression appeared to be modulated by the frequency of compressions such that a higher frequency (15 cycles/min) evoked more robust changes in VEGF and MCP-1 compared with a lower frequency (3 cycles/min).

  20. Prophylactic knee bracing alters lower-limb muscle forces during a double-leg drop landing.

    Science.gov (United States)

    Ewing, Katie A; Fernandez, Justin W; Begg, Rezaul K; Galea, Mary P; Lee, Peter V S

    2016-10-03

    Anterior cruciate ligament (ACL) injury can be a painful, debilitating and costly consequence of participating in sporting activities. Prophylactic knee bracing aims to reduce the number and severity of ACL injury, which commonly occurs during landing maneuvers and is more prevalent in female athletes, but a consensus on the effectiveness of prophylactic knee braces has not been established. The lower-limb muscles are believed to play an important role in stabilizing the knee joint. The purpose of this study was to investigate the changes in lower-limb muscle function with prophylactic knee bracing in male and female athletes during landing. Fifteen recreational athletes performed double-leg drop landing tasks from 0.30m and 0.60m with and without a prophylactic knee brace. Motion analysis data were used to create subject-specific musculoskeletal models in OpenSim. Static optimization was performed to calculate the lower-limb muscle forces. A linear mixed model determined that the hamstrings and vasti muscles produced significantly greater flexion and extension torques, respectively, and greater peak muscle forces with bracing. No differences in the timings of peak muscle forces were observed. These findings suggest that prophylactic knee bracing may help to provide stability to the knee joint by increasing the active stiffness of the hamstrings and vasti muscles later in the landing phase rather than by altering the timing of muscle forces. Further studies are necessary to quantify whether prophylactic knee bracing can reduce the load placed on the ACL during intense dynamic movements. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. BUILDING A BETTER GLUTEAL BRIDGE: ELECTROMYOGRAPHIC ANALYSIS OF HIP MUSCLE ACTIVITY DURING MODIFIED SINGLE-LEG BRIDGES

    Science.gov (United States)

    Edwards, Michael; Haverkamp, Ryan; Martin, Lani; Porter, Kambry; Thach, Kailey; Sack, Richard J.; Hakansson, Nils A.

    2017-01-01

    Background Gluteal strength plays a role in injury prevention, normal gait patterns, eliminating pain, and enhancing athletic performance. Research shows high gluteal muscle activity during a single-leg bridge compared to other gluteal strengthening exercises; however, prior studies have primarily measured muscle activity with the active lower extremity starting in 90 ° of knee flexion with an extended contralateral knee. This standard position has caused reports of hamstring cramping, which may impede optimal gluteal strengthening. Hypothesis/Purpose The purpose of this study was to determine which modified position for the single-leg bridge is best for preferentially activating the gluteus maximus and medius. Study Design Cross-Sectional Methods Twenty-eight healthy males and females aged 18-30 years were tested in five different, randomized single-leg bridge positions. Electromyography (EMG) electrodes were placed on subjects’ gluteus maximus, gluteus medius, rectus femoris, and biceps femoris of their bridge leg (i.e., dominant or kicking leg), as well as the rectus femoris of their contralateral leg. Subjects performed a maximal voluntary isometric contraction (MVIC) for each tested muscle prior to performing five different bridge positions in randomized order. All bridge EMG data were normalized to the corresponding muscle MVIC data. Results A modified bridge position with the knee of the bridge leg flexed to 135 ° versus the traditional 90 ° of knee flexion demonstrated preferential activation of the gluteus maximus and gluteus medius compared to the traditional single-leg bridge. Hamstring activation significantly decreased (p gluteus maximus and medius, respectively). Conclusion Modifying the traditional single-leg bridge by flexing the active knee to 135 ° instead of 90 ° minimizes hamstring activity while maintaining high levels of gluteal activation, effectively building a bridge better suited for preferential gluteal activation

  2. Distal muscle activity alterations during the stance phase of gait in restless leg syndrome (RLS) patients.

    Science.gov (United States)

    Dafkin, Chloe; Green, Andrew; Olivier, Benita; McKinon, Warrick; Kerr, Samantha

    2018-05-01

    To assess if there is a circadian variation in electromyographical (EMG) muscle activity during gait in restless legs syndrome (RLS) patients and healthy control participants. Gait assessment was done in 14 RLS patients and 13 healthy control participants in the evening (PM) and the morning (AM). Muscle activity was recorded bilaterally from the tibialis anterior (TA), lateral gastrocnemius (GL), rectus femoris (RF) and biceps femoris (BF) muscles. A circadian variation during the stance phase in only TA (PM > AM, p  Controls, p < 0.05) during early stance and decreased GL activity (RLS < Controls, p < 0.01) during terminal stance in comparison to control participants in the evening. No other significant differences were noted between RLS patients and control participants. Activation of GL during the swing phase was noted in 79% of RLS patients and in 23% of control participants in the morning compared to 71% and 38% in the evening, respectively. EMG muscle activity shows no circadian variation in RLS patients. Evening differences in gait muscle activation patterns between RLS patients and control participants are evident. These results extend our knowledge about alterations in spinal processing during gait in RLS. A possible explanation for these findings is central pattern generator sensitization caused by increased sensitivity in cutaneous afferents in RLS patients. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. The role of eccentric regime of leg muscle work in alpine skiing

    Directory of Open Access Journals (Sweden)

    Ropret Robert

    2017-01-01

    Full Text Available Alpine skiing is characterized by a great number of leg movements with muscle contractions in eccentric regime. The role of these movements is to absorb gravitation and inertial forces, manage skis more precisely and maintain balance. Recent studies have determined the volume, duration and intenisty of eccentric contractions as well as the basic characteristics of movement amplitudes and velocities. Based on the previous findings the experiments involving eccentric training using a bicycle ergometer confirmed a positive impact that this kind of training has on increasing maximum power, strength, endurance, coordination, injury prevention, metabolic work efficiency, more efficient work with longer muscle length and its role in miming skiers' movements. This paper is an review of the studies so far in the field of kinematics, skiing dynamics and the effect of eccentric training on the development of athletes' performances.

  4. Muscle activity during leg strengthening exercise using free weights and elastic resistance

    DEFF Research Database (Denmark)

    Jakobsen, Markus Due; Sundstrup, Emil; Andersen, Christoffer H

    2013-01-01

    The present study's aim was to evaluate muscle activity during leg exercises using elastic vs. isoinertial resistance at different exertion and loading levels, respectively. Twenty-four women and eighteen men aged 26-67 years volunteered to participate in the experiment. Electromyographic (EMG......) activity was recorded in nine muscles during a standardized forward lunge movement performed with dumbbells and elastic bands during (1) ballistic vs. controlled exertion, and (2) at low, medium and high loads (33%, 66% and 100% of 10 RM, respectively). The recorded EMG signals were normalized to MVC EMG....... Knee joint angle was measured using electronic inclinometers. The following results were obtained. Loading intensity affected EMG amplitude in the order: low...

  5. Muscle fatigue and exhaustion during dynamic leg exercise in normoxia and hypobaric hypoxia

    DEFF Research Database (Denmark)

    Fulco, C S; Lewis, S F; Frykman, Peter

    1996-01-01

    Using an exercise device that integrates maximal voluntary static contraction (MVC) of knee extensor muscles with dynamic knee extension, we compared progressive muscle fatigue, i.e., rate of decline in force-generating capacity, in normoxia (758 Torr) and hypobaric hypoxia (464 Torr). Eight...... healthy men performed exhaustive constant work rate knee extension (21 +/- 3 W, 79 +/- 2 and 87 +/- 2% of 1-leg knee extension O2 peak uptake for normoxia and hypobaria, respectively) from knee angles of 90-150 degrees at a rate of 1 Hz. MVC (90 degrees knee angle) was performed before dynamic exercise...... and during MVC force was 578 +/- 29 N in normoxia and 569 +/- 29 N in hypobaria before exercise and fell, at exhaustion, to similar levels (265 +/- 10 and 284 +/- 20 N for normoxia and hypobaria, respectively; P > 0.05) that were higher (P

  6. Volume estimation of extensor muscles of the lower leg based on MR imaging

    International Nuclear Information System (INIS)

    Lund, Hans; Christensen, Line; Savnik, Anette; Danneskiold-Samsoee, Bente; Bliddal, Henning; Boesen, Jens

    2002-01-01

    Magnetic resonance imaging can be used to measure the muscle volume of a given muscle or muscle group. The purpose of this study was to determine both the intra- and inter-observer variation of the manually outlined volume of the extensor muscles (tibialis anterior, extensor digitorum longus and extensor hallucis longus), to estimate the minimum number of slices needed for these calculations and to compare estimates of volume based on an assumed conic shape of the muscles with that of an assumed cylindrical shape, the calculation in both cases based on the Cavalieri principle. Eleven young and healthy subjects (4 women and 7 men, age range 24-40 years) participated. Magnetic resonance imaging of the left leg was obtained on a 1.5-T MR system using a knee coil (receive only). A total of 50 consecutive slices were obtained beginning 10 cm below the caput fibula sin. and proceeding distally with a slice thickness of 1.5 mm without gap. The intra-class correlation coefficient (ICC) was used to calculate the relative reliability (interval from 0 to 1.0). A high reliability for both intra- and inter-reliability was observed (ICC 0.98 and 1.0). The difference was only 0.004% between calculations based on measurement of all 50 slices with respect to 8 slices equally distributed along the muscle group. No difference was found between the two different volumetric assumptions in the Cavalieri principle. The manually outlining of extensor muscles volumes was reliable and only 8 slices of the calf were needed. No difference was seen between the two used mathematical calculations. (orig.)

  7. Volume estimation of extensor muscles of the lower leg based on MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lund, Hans; Christensen, Line; Savnik, Anette; Danneskiold-Samsoee, Bente; Bliddal, Henning [The Parker Institute, Frederiksberg Hospital, 2000 Frederiksberg (Denmark); Boesen, Jens [Department of Radiology, Frederiksberg Hospital, 2000 Frederiksberg (Denmark)

    2002-12-01

    Magnetic resonance imaging can be used to measure the muscle volume of a given muscle or muscle group. The purpose of this study was to determine both the intra- and inter-observer variation of the manually outlined volume of the extensor muscles (tibialis anterior, extensor digitorum longus and extensor hallucis longus), to estimate the minimum number of slices needed for these calculations and to compare estimates of volume based on an assumed conic shape of the muscles with that of an assumed cylindrical shape, the calculation in both cases based on the Cavalieri principle. Eleven young and healthy subjects (4 women and 7 men, age range 24-40 years) participated. Magnetic resonance imaging of the left leg was obtained on a 1.5-T MR system using a knee coil (receive only). A total of 50 consecutive slices were obtained beginning 10 cm below the caput fibula sin. and proceeding distally with a slice thickness of 1.5 mm without gap. The intra-class correlation coefficient (ICC) was used to calculate the relative reliability (interval from 0 to 1.0). A high reliability for both intra- and inter-reliability was observed (ICC 0.98 and 1.0). The difference was only 0.004% between calculations based on measurement of all 50 slices with respect to 8 slices equally distributed along the muscle group. No difference was found between the two different volumetric assumptions in the Cavalieri principle. The manually outlining of extensor muscles volumes was reliable and only 8 slices of the calf were needed. No difference was seen between the two used mathematical calculations. (orig.)

  8. Different fatigue-resistant leg muscles and EMG response during whole-body vibration.

    Science.gov (United States)

    Simsek, Deniz

    2017-12-01

    The purpose of this study was to determine the effects of static whole-body vibration (WBV) on the Electromyograhic (EMG) responses of leg muscles, which are fatigue-resistant in different manner. The study population was divided into two groups according to the values obtained by the Fatigue Index [Group I: Less Fatigue Resistant (LFR), n=11; Group II: More Fatigue Resistant (MFR), n=11]. The repeated electromyographic (EMG) activities of four leg muscles were analyzed the following determinants: (1) frequency (30 Hz, 35 Hz and 40 Hz); (2) stance position (static squat position); (3) amplitude (2 mm and 4 mm) and (4) knee flexion angle (120°), (5) vertical vibration platform. Vibration data were analyzed using Minitab 16 (Minitab Ltd, State College, PA, USA). The significance level was set at pmuscle fatigue (pEMG activation at higher frequencies (max at 40 Hz) and amplitudes (4 mm) (p<.05). The present study can be used for the optimal prescription of vibration exercise and can serve to guide the development of training programs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. ACTN3 R577X polymorphism and explosive leg-muscle power in elite basketball players.

    Science.gov (United States)

    Garatachea, Nuria; Verde, Zoraida; Santos-Lozano, Alejandro; Yvert, Thomas; Rodriguez-Romo, Gabriel; Sarasa, Francisco J; Hernández-Sánchez, Sonsoles; Santiago, Catalina; Lucia, Alejandro

    2014-03-01

    To determine the association of the ACTN3 R577X polymorphism with leg-muscle explosive power in Spanish (white) elite basketball players and controls. 100 (60 men) elite basketball players (cases) and 283 nonathletic controls. The authors assessed power performance by means of the vertical-squat and countermovement-jump tests. Genotype distributions did not differ between groups (cases: 37.0% [RR], 42.0% [RX], and 21.0% [XX]; controls: 31.8% [RR], 49.8% [RX], and 18.4% [XX]; P = .353). The authors did not observe any effect of the ACTN3 R577X polymorphism on study phenotypes in either group, including when they performed the analyses separately in men and women. They found no association between the ACTN3 R577X polymorphism and the likelihood of being an elite basketball player using the dominant or the recessive model, and the results remained unaltered when the analyses were adjusted for sex, weight, height, and age or when performed for men and women separately. Although the ACTN3 R577X is associated with explosive muscle performance and this phenotype is important in the sport of basketball (ie, during jumps), the authors found no association with leg explosive power in elite basket players or with the status of being this type of athlete.

  10. BUILDING A BETTER GLUTEAL BRIDGE: ELECTROMYOGRAPHIC ANALYSIS OF HIP MUSCLE ACTIVITY DURING MODIFIED SINGLE-LEG BRIDGES.

    Science.gov (United States)

    Lehecka, B J; Edwards, Michael; Haverkamp, Ryan; Martin, Lani; Porter, Kambry; Thach, Kailey; Sack, Richard J; Hakansson, Nils A

    2017-08-01

    Gluteal strength plays a role in injury prevention, normal gait patterns, eliminating pain, and enhancing athletic performance. Research shows high gluteal muscle activity during a single-leg bridge compared to other gluteal strengthening exercises; however, prior studies have primarily measured muscle activity with the active lower extremity starting in 90 ° of knee flexion with an extended contralateral knee. This standard position has caused reports of hamstring cramping, which may impede optimal gluteal strengthening. The purpose of this study was to determine which modified position for the single-leg bridge is best for preferentially activating the gluteus maximus and medius. Cross-Sectional. Twenty-eight healthy males and females aged 18-30 years were tested in five different, randomized single-leg bridge positions. Electromyography (EMG) electrodes were placed on subjects' gluteus maximus, gluteus medius, rectus femoris, and biceps femoris of their bridge leg (i.e., dominant or kicking leg), as well as the rectus femoris of their contralateral leg. Subjects performed a maximal voluntary isometric contraction (MVIC) for each tested muscle prior to performing five different bridge positions in randomized order. All bridge EMG data were normalized to the corresponding muscle MVIC data. A modified bridge position with the knee of the bridge leg flexed to 135 ° versus the traditional 90 ° of knee flexion demonstrated preferential activation of the gluteus maximus and gluteus medius compared to the traditional single-leg bridge. Hamstring activation significantly decreased (p bridge by flexing the active knee to 135 ° instead of 90 ° minimizes hamstring activity while maintaining high levels of gluteal activation, effectively building a bridge better suited for preferential gluteal activation. 3.

  11. The Effects of Active Straight Leg Raising on Tonicity and Activity of Pelvic Stabilizer Muscles

    Directory of Open Access Journals (Sweden)

    Azadeh Shadmehr

    2011-01-01

    Full Text Available Objective: Active straight leg raising (SLR test is advocated as a valid diagnostic method in diagnosis of sacroiliac joint (SIJ dysfunction that can assess the quality of load transfer between trunk and lower limb. The aim of this study is Comparison of changes in tonicity and activity of pelvic stabilizer muscles during active SLR, between healthy individuals and patients with sacroiliac joint pain. Materials & Methods: A case – control study was designed in 26 women (19-50 years old. With use of simple sampling, surface electromyography from rectus abdominis, external oblique, internal oblique, adductor longus, erector spine, gluteus maximus and biceps femoris was recorded in 26 subjects (15 healthy females and 11 females with sacroiliac pain in resting position and during active SLR test. Resting muscle tonicity and rms during ramp time and hold time in active SLR test were assessed by non parametric-two independent sample test. Results: Biceps femoris activity in resting position was significantly larger in patients group (P<0.05. During the active SLR, the women with sacroiliac joint pain used much less activity in some pelvic stabilizer muscles compared to the healthy subjects (P<0.05. Conclusion: The increased resting tonicity of biceps femoris and decreased activity of pelvic stabilizer muscles in subjects with sacroiliac joint pain, suggests an alteration in the strategy for lumbopelvic stabilization that may disrupt load transference through the pelvis.

  12. Structural Response of Lower Leg Muscles in Compression: A Low Impact Energy Study Employing Volunteers, Cadavers and the Hybrid III.

    Science.gov (United States)

    Dhaliwal, Trilok S; Beillas, Philippe; Chou, Clifford C; Prasad, Priya; Yang, King H; King, Albert I

    2002-11-01

    Little has been reported in the literature on the compressive properties of muscle. These data are needed for the development of finite element models that address impact of the muscles, especially in the study of pedestrian impact. Tests were conducted to characterize the compressive response of muscle. Volunteers, cadaveric specimens and a Hybrid III dummy were impacted in the posterior and lateral aspect of the lower leg using a free flying pendulum. Volunteer muscles were tested while tensed and relaxed. The effects of muscle tension were found to influence results, especially in posterior leg impacts. Cadaveric response was found to be similar to that of the relaxed volunteer. The resulting data can be used to identify a material law using an inverse method.

  13. The Effect of Electrical Stimulation of the Calf Muscle on Leg Fluid Accumulation over a Long Period of Sitting.

    Science.gov (United States)

    Vena, Daniel; Rubianto, Jonathan; Popovic, Milos R; Fernie, Geoff R; Yadollahi, Azadeh

    2017-07-20

    Leg fluid accumulation during sedentary behaviours such as sitting can lead to leg edema and associated adverse health consequences. This study investigates the use calf muscle electrical stimulation (ES) to reduce seated leg fluid accumulation. Thirteen non-obese, normotensive men (mean age 51 yr.) with sleep apnea were enrolled in the study. Participants first lay supine for 30 minutes to equalize fluid distribution and then sat for 150 minutes. While seated, participants received either active or sham ES of the calf muscles, according to random assignment. Participants returned one-week later to cross over to the other study condition. Leg fluid was measured continuously while sitting using the bioelectrical impedance method. Fluid accumulation in the leg was reduced by more than 40% using active ES, compared to sham ES (∆ = 51.9 ± 8.8 ml vs. ∆ = 91.5 ± 8.9 ml, P calf muscle ES is an effective method for reducing accumulation of fluid during long sedentary periods and has potential use as a device for preventing leg edema to treat associated health consequences in at-risk groups and settings.

  14. Neural adjustment in the activation of the lower leg muscles through daily physical exercises in community-based elderly persons.

    Science.gov (United States)

    Maejima, Hiroshi; Murase, Azusa; Sunahori, Hitoshi; Kanetada, Yuji; Otani, Takuya; Yoshimura, Osamu; Tobimatsu, Yoshiko

    2007-02-01

    Reflecting the rapidly aging population, community-based interventions in the form of physical exercise have been introduced to promote the health of elderly persons. Many investigation studies have focused on muscle strength in the lower leg as a potent indicator of the effect of physical exercises. The objective of this study was to assess the effect of long-term daily exercises on neural command in lower leg muscle activations. Twenty-six community-based elderly persons (13 men and 13 women; 69.8 +/- 0.5 years old) participated in this study. Daily exercise was comprised of walking for more than 30 min, stretching, muscle strengthening and balance exercise, and was continued for three months. Muscle strength and surface electromyography of the tibia anterior, rectus femoris, and biceps femoris were measured in maximum isometric voluntary contraction both before and after the intervention. The mean frequency of the firing of motor units was calculated based on fast Fourier transformation of the electromyography. As the results of the intervention, muscle strength increased significantly only in biceps femoris, whereas the mean frequency of motor units decreased significantly in every muscle, indicating that motor unit firing in lower frequency efficiently induces the same or greater strength compared with before the intervention. Thus, synchronization of motor units compensates for the lower frequency of motor unit firing to maintain muscular strength. In conclusion, long-term physical exercises in the elderly can modulate the neural adjustment of lower leg muscles to promote efficient output of muscle strength.

  15. Muscle stiffness of posterior lower leg in runners with a history of medial tibial stress syndrome.

    Science.gov (United States)

    Saeki, J; Nakamura, M; Nakao, S; Fujita, K; Yanase, K; Ichihashi, N

    2018-01-01

    Previous history of medial tibial stress syndrome (MTSS) is a risk factor for MTSS relapse, which suggests that there might be some physical factors that are related to MTSS development in runners with a history of MTSS. The relationship between MTSS and muscle stiffness can be assessed in a cross-sectional study that measures muscle stiffness in subjects with a history of MTSS, who do not have pain at the time of measurement, and in those without a history of MTSS. The purpose of this study was to compare the shear elastic modulus, which is an index of muscle stiffness, of all posterior lower leg muscles of subjects with a history of MTSS and those with no history and investigate which muscles could be related to MTSS. Twenty-four male collegiate runners (age, 20.0±1.7 years; height, 172.7±4.8 cm; weight, 57.3±3.7 kg) participated in this study; 14 had a history of MTSS, and 10 did not. The shear elastic moduli of the lateral gastrocnemius, medial gastrocnemius, soleus, peroneus longus, peroneus brevis, flexor hallucis longus, flexor digitorum longus, and tibialis posterior were measured using shear wave elastography. The shear elastic moduli of the flexor digitorum longus and tibialis posterior were significantly higher in subjects with a history of MTSS than in those with no history. However, there was no significant difference in the shear elastic moduli of other muscles. The results of this study suggest that flexor digitorum longus and tibialis posterior stiffness could be related to MTSS. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  16. Muscle strength rather than muscle mass is associated with osteoporosis in older Chinese adults

    Directory of Open Access Journals (Sweden)

    Yixuan Ma

    2018-02-01

    Conclusion: Based on our study, muscle strength rather than muscle mass is negatively associated with OS in older people; thus, we should pay more attention to muscle strength training in the early stage of the OS.

  17. Intermittent pneumatic compression of legs increases microcirculation in distant skeletal muscle.

    Science.gov (United States)

    Liu, K; Chen, L E; Seaber, A V; Johnson, G W; Urbaniak, J R

    1999-01-01

    Intermittent pneumatic compression has been established as a method of clinically preventing deep vein thrombosis, but the mechanism has not been documented. This study observed the effects of intermittent pneumatic compression of legs on the microcirculation of distant skeletal muscle. The cremaster muscles of 80 male rats were exposed, a specially designed intermittent pneumatic-compression device was applied to both legs for 60 minutes, and the microcirculation of the muscles was assessed by measurement of the vessel diameter in three categories (10-20, 21-40, and 41-70 microm) for 120 minutes. The results showed significant vasodilation in arterial and venous vessels during the application of intermittent pneumatic compression, which disappeared after termination of the compression. The vasodilation reached a maximum 30 minutes after initiation of the compression and could be completely blocked by an inhibitor of nitric oxide synthase, NG-monomethyl-L-arginine (10 micromol/min). A 120-minute infusion of NG-monomethyl-L-arginine, beginning coincident with 60 minutes of intermittent pneumatic compression, resulted in a significant decrease in arterial diameter that remained at almost the same level after termination of the compression. The magnitude of the decrease in diameter in the group treated with intermittent pneumatic compression and NG-monomethyl-L-arginine was comparable with that in the group treated with NG-monomethyl-L-arginine alone. The results imply that the production of nitric oxide is involved in the positive influence of intermittent pneumatic compression on circulation. It is postulated that the rapid increase in venous velocity induced by intermittent pneumatic compression produces strong shear stress on the vascular endothelium, which stimulates an increased release of nitric oxide and thereby causes systemic vasodilation.

  18. Muscle Mass and Weight Gain Nutritional Supplements

    Science.gov (United States)

    Campbell, Bill

    There are numerous sports supplements available that claim to increase lean body mass. However, for these sports supplements to exert any favorable changes in lean body mass, they must influence those factors regulating skeletal muscle hypertrophy (i.e., satellite cell activity, gene transcription, protein translation). If a given sports supplement does favorably influence one of these regulatory factors, the result is a positive net protein balance (in which protein synthesis exceeds protein breakdown). Sports supplement categories aimed at eliciting a positive net protein balance include anabolic hormone enhancers, nutrient timing pre- and postexercise workout supplements, anticatabolic supplements, and nitric oxide boosters. Of all the sports supplements available, only a few have been subject to multiple clinical trials with repeated favorable outcomes relative to increasing lean body mass. This chapter focuses on these supplements and others that have a sound theoretical rationale in relation to increasing lean body mass.

  19. Postmortem changes in physiochemical and sensory properties of red snow crab (Chionoecetes japonicus leg muscle during freeze storage

    Directory of Open Access Journals (Sweden)

    Joon-Young Jun

    2017-07-01

    Full Text Available Abstract In order to evaluate the maximal storable period of the raw crab for a non-thermal muscle separation, the quality changes of the leg meat of red snow crab (Chionoecetes japonicus during freeze storage were investigated. Fresh red snow crabs were stored at −20 °C for 7 weeks, and the leg muscle was separated by a no heating separation (NHS method every week. During the storage, considerable loss of the leg muscle did not occur and microbiological risk was very low. In contrast, discoloration appeared at 2-week storage on around carapace and the leg muscle turned yellow at storage 3-week. In physiochemical parameters, protein and free amino acids gradually decreased with storage time, expected that proteolytic enzymes still activated at −20 °C. At 4-week storage, the sensory acceptance dropped down below point 4 as low as inedible and notable inflection points in pH and acidity were observed. The volatile base nitrogen was low, though a little increase was recorded. These results suggested that the maximal storable period at −20 °C of the raw material was within 2 weeks and it was depended on external factor such as the discoloration. The present study might be referred as basic data for approaches to solve quality loss occurred in non-thermal muscle separation.

  20. Leg mass characteristics of accurate and inaccurate kickers--an Australian football perspective.

    Science.gov (United States)

    Hart, Nicolas H; Nimphius, Sophia; Cochrane, Jodie L; Newton, Robert U

    2013-01-01

    Athletic profiling provides valuable information to sport scientists, assisting in the optimal design of strength and conditioning programmes. Understanding the influence these physical characteristics may have on the generation of kicking accuracy is advantageous. The aim of this study was to profile and compare the lower limb mass characteristics of accurate and inaccurate Australian footballers. Thirty-one players were recruited from the Western Australian Football League to perform ten drop punt kicks over 20 metres to a player target. Players were separated into accurate (n = 15) and inaccurate (n = 16) groups, with leg mass characteristics assessed using whole body dual energy x-ray absorptiometry (DXA) scans. Accurate kickers demonstrated significantly greater relative lean mass (P ≤ 0.004) and significantly lower relative fat mass (P ≤ 0.024) across all segments of the kicking and support limbs, while also exhibiting significantly higher intra-limb lean-to-fat mass ratios for all segments across both limbs (P ≤ 0.009). Inaccurate kickers also produced significantly larger asymmetries between limbs than accurate kickers (P ≤ 0.028), showing considerably lower lean mass in their support leg. These results illustrate a difference in leg mass characteristics between accurate and inaccurate kickers, highlighting the potential influence these may have on technical proficiency of the drop punt.

  1. Muscle mass, muscle strength, and muscle fat infiltration as predictors of incident mobility limitations in well-functioning older persons

    NARCIS (Netherlands)

    Visser, Marjolein; Goodpaster, Bret H; Kritchevsky, Stephen B; Newman, Anne B; Nevitt, Michael; Rubin, Susan M; Simonsick, Eleanor M; Harris, Tamara B

    BACKGROUND: Lower muscle mass has been correlated with poor physical function; however, no studies have examined this relationship prospectively. This study aims to investigate whether low muscle mass, low muscle strength, and greater fat infiltration into the muscle predict incident mobility

  2. Obesity Appears to Be Associated With Altered Muscle Protein Synthetic and Breakdown Responses to Increased Nutrient Delivery in Older Men, but Not Reduced Muscle Mass or Contractile Function.

    Science.gov (United States)

    Murton, Andrew J; Marimuthu, Kanagaraj; Mallinson, Joanne E; Selby, Anna L; Smith, Kenneth; Rennie, Michael J; Greenhaff, Paul L

    2015-09-01

    Obesity is increasing, yet despite the necessity of maintaining muscle mass and function with age, the effect of obesity on muscle protein turnover in older adults remains unknown. Eleven obese (BMI 31.9 ± 1.1 kg · m(-2)) and 15 healthy-weight (BMI 23.4 ± 0.3 kg · m(-2)) older men (55-75 years old) participated in a study that determined muscle protein synthesis (MPS) and leg protein breakdown (LPB) under postabsorptive (hypoinsulinemic-euglycemic clamp) and postprandial (hyperinsulinemic hyperaminoacidemic-euglycemic clamp) conditions. Obesity was associated with systemic inflammation, greater leg fat mass, and patterns of mRNA expression consistent with muscle deconditioning, whereas leg lean mass, strength, and work done during maximal exercise were no different. Under postabsorptive conditions, MPS and LPB were equivalent between groups, whereas insulin and amino acid administration increased MPS in only healthy-weight subjects and was associated with lower leg glucose disposal (LGD) (63%) in obese men. Blunting of MPS in the obese men was offset by an apparent decline in LPB, which was absent in healthy-weight subjects. Lower postprandial LGD in obese subjects and blunting of MPS responses to amino acids suggest that obesity in older adults is associated with diminished muscle metabolic quality. This does not, however, appear to be associated with lower leg lean mass or strength. © 2015 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

  3. [Blood distribution in the human leg arteries during orthostasis: role of the hydrostatic factor and posturotonic straining of the anti-gravity muscles].

    Science.gov (United States)

    Modin, A Iu

    2004-01-01

    Ultrasonic visualization and dopplerography were used to study volumetric blood flows along the femoral artery, deep artery of the thigh, and the popliteal and sural arteries in normal volunteers. Active standing test resulted in significant blood redistribution among the arteries with prioritized blood supply to predominantly anti-g muscles but not to predominantly locomotor muscles. Elimination of static loading on the anti-g muscles by weight removal (transfer of the body mass on the other leg) was conducive to the opposite effect, i.e. absolute and relative decreases in the intensity of blood flow along the sural artery and a relatively more marked blood redistribution toward the deep artery of the thigh.

  4. The effect of creatine supplementation on mass and performance of rat skeletal muscle.

    Science.gov (United States)

    Young, Robert E; Young, John C

    2007-08-09

    This study investigated the effect of dietary creatine supplementation on hypertrophy and performance of rat skeletal muscle. Male Sprague-Dawley rats underwent either tibialis anterior ablation or partial ablation of the plantaris/gastrocnemius to induce compensatory hypertrophy of the extensor digitorum longus (EDL) or soleus respectively, or sham surgery. Creatine (300 mg/kg) was administered to one half of each group for 5 weeks, after which force production was measured. With the leg fixed at the knee and ankle, the distal tendon of the EDL or soleus was attached to a force transducer and the muscle was electrically stimulated via the sciatic nerve. Synergist ablation resulted in a significant increase in EDL mass and in soleus mass relative to control muscles. However, no effect of creatine supplementation on muscle mass or performance was found between control and either group of creatine-treated rats. Despite an apparent increase in muscle creatine content, creatine supplementation did not augment muscle hypertrophy or force production in rat EDL or soleus muscle, providing evidence that the potential benefits of creatine supplementation are not due to a direct effect on muscle but rather to an enhanced ability to train.

  5. A neuro-mechanical model of a single leg joint highlighting the basic physiological role of fast and slow muscle fibres of an insect muscle system.

    Directory of Open Access Journals (Sweden)

    Tibor Istvan Toth

    Full Text Available In legged animals, the muscle system has a dual function: to produce forces and torques necessary to move the limbs in a systematic way, and to maintain the body in a static position. These two functions are performed by the contribution of specialized motor units, i.e. motoneurons driving sets of specialized muscle fibres. With reference to their overall contraction and metabolic properties they are called fast and slow muscle fibres and can be found ubiquitously in skeletal muscles. Both fibre types are active during stepping, but only the slow ones maintain the posture of the body. From these findings, the general hypothesis on a functional segregation between both fibre types and their neuronal control has arisen. Earlier muscle models did not fully take this aspect into account. They either focused on certain aspects of muscular function or were developed to describe specific behaviours only. By contrast, our neuro-mechanical model is more general as it allows functionally to differentiate between static and dynamic aspects of movement control. It does so by including both muscle fibre types and separate motoneuron drives. Our model helps to gain a deeper insight into how the nervous system might combine neuronal control of locomotion and posture. It predicts that (1 positioning the leg at a specific retraction angle in steady state is most likely due to the extent of recruitment of slow muscle fibres and not to the force developed in the individual fibres of the antagonistic muscles; (2 the fast muscle fibres of antagonistic muscles contract alternately during stepping, while co-contraction of the slow muscle fibres takes place during steady state; (3 there are several possible ways of transition between movement and steady state of the leg achieved by varying the time course of recruitment of the fibres in the participating muscles.

  6. Influence of shoes and foot orthoses on lower extremity muscle activation onset times in healthy subjects during the transition from double-leg stance to single-leg stance.

    Science.gov (United States)

    Dingenen, B; Peeraer, L; Deschamps, K; Fieuws, S; Janssens, L; Staes, F

    2015-01-01

    The aim of this study was to evaluate the influence of shoes and foot orthoses on lower extremity muscle activation patterns in healthy subjects during the transition from double-leg stance to single-leg stance. Eight male and seven female young asymptomatic adults who wear foot orthoses were recruited. Muscle activation onset times of 9 lower extremity muscles were recorded using surface electromyography during the transition from double-leg stance to single-leg stance, performed with eyes open and with eyes closed. This was tested in 4 experimental conditions: 1) barefoot (BF); 2) shoes only (SO); 3) shoes with standardized FO (SSFO); and 4) shoes with customized FO (SCFO). Based on a four-way (condition-region-leg-vision) linear model for repeated measures, we found a significant condition effect (P=0.025). Differences between conditions did not depend on the leg and/or the vision condition, but on the region (ankle-knee-hip). Based on a two-way (condition-muscle) linear model within each region, only significant differences between conditions for peroneus longus (P=0.003) were found. The onset times of peroneus longus were significantly earlier in SO (P=0.029) and SCFO (P=0.001) compared to BF. These results indicate that SO and SCFO can accelerate peroneus longus muscle activation onset times during the transition from double-leg stance to single-leg stance. Further research is required to determine how these adaptations may develop over time.

  7. Leg Injuries and Disorders

    Science.gov (United States)

    Your legs are made up of bones, blood vessels, muscles, and other connective tissue. They are important for motion ... falling, or having an accident can damage your legs. Common leg injuries include sprains and strains, joint ...

  8. Factors related to skeletal muscle mass in the frail elderly.

    Science.gov (United States)

    Sagawa, Keiichiro; Kikutani, Takeshi; Tamura, Fumiyo; Yoshida, Mitsuyoshi

    2017-01-01

    It is important for the elderly to maintain their skeletal muscle mass, which in turn helps to maintain physical functions. This study aimed to clarify factors related to skeletal muscle mass maintenance. Home-bound elderly (94 men and 216 women), at least 75 years of age, attending a day-care center in Tokyo, were enrolled in this study. Dentists specializing in dysphagia rehabilitation evaluated skeletal muscle mass, occlusal status and swallowing function. Physical function, cognitive function and nutritional status were also evaluated by interviewing caregivers. Correlations of skeletal muscle mass with various factors were determined in each gender group. Multiple regression analysis revealed that skeletal muscle mass was significantly related to nutritional status in both men and women. In men, there was a significant difference in skeletal muscle mass between those with and without occlusion of the natural teeth. Our results suggest that dental treatments and dentures would be useful for maintaining skeletal muscle mass, especially in men.

  9. Tracking control of a leg rehabilitation machine driven by pneumatic artificial muscles using composite fuzzy theory.

    Science.gov (United States)

    Chang, Ming-Kun

    2014-01-01

    It is difficult to achieve excellent tracking performance for a two-joint leg rehabilitation machine driven by pneumatic artificial muscles (PAMs) because the system has a coupling effect, highly nonlinear and time-varying behavior associated with gas compression, and the nonlinear elasticity of bladder containers. This paper therefore proposes a T-S fuzzy theory with supervisory control in order to overcome the above problems. The T-S fuzzy theory decomposes the model of a nonlinear system into a set of linear subsystems. In this manner, the controller in the T-S fuzzy model is able to use simple linear control techniques to provide a systematic framework for the design of a state feedback controller. Then the LMI Toolbox of MATLAB can be employed to solve linear matrix inequalities (LMIs) in order to determine controller gains based on the Lyapunov direct method. Moreover, the supervisory control can overcome the coupling effect for a leg rehabilitation machine. Experimental results show that the proposed controller can achieve excellent tracking performance, and guarantee robustness to system parameter uncertainties.

  10. Relationships Between Lower-Body Muscle Structure and, Lower-Body Strength, Explosiveness and Eccentric Leg Stiffness in Adolescent Athletes.

    Science.gov (United States)

    Secomb, Josh L; Nimphius, Sophia; Farley, Oliver R L; Lundgren, Lina E; Tran, Tai T; Sheppard, Jeremy M

    2015-12-01

    The purpose of the present study was to determine whether any relationships were present between lower-body muscle structure and, lower-body strength, variables measured during a countermovement jump (CMJ) and squat jump (SJ), and eccentric leg stiffness, in adolescent athletes. Thirty junior male (n = 23) and female (n = 7) surfing athletes (14.8 ± 1.7 y; 1.63 ± 0.09 m; 54.8 ± 12.1 kg) undertook lower-body muscle structure assessment with ultrasonography and performed a; CMJ, SJ and an isometric mid-thigh pull (IMTP). In addition, eccentric leg stiffness was calculated from variables of the CMJ and IMTP. Moderate to very large relationships (r = 0.46-0.73) were identified between the thickness of the vastus lateralis (VL) and lateral gastrocnemius (LG) muscles, and VL pennation angle and; peak force (PF) in the CMJ, SJ and IMTP. Additionally, moderate to large relationships (r = 0.37-0.59) were found between eccentric leg stiffness and; VL and LG thickness, VL pennation angle, and LG fascicle length, with a large relationship (r = 0.59) also present with IMTP PF. These results suggest that greater thickness of the VL and LG were related to improved maximal dynamic and isometric strength, likely due to increased hypertrophy of the extensor muscles. Furthermore, this increased thickness was related to greater eccentric leg stiffness, as the associated enhanced lower-body strength likely allowed for greater neuromuscular activation, and hence less compliance, during a stretch-shortening cycle. Key pointsGreater thickness of the VL and LG muscles were significantly related to an enhanced ability to express higher levels of isometric and dynamic strength, and explosiveness in adolescent athletes.Isometric strength underpinned performance in the CMJ and SJ in these athletes.Greater lower-body isometric strength was significantly related to eccentric leg stiffness, which is potentially the result of greater neuromuscular activation in the muscle-tendon unit.

  11. Pneumatic Artificial Muscles Force Modelling and the Position and Stiffness Control on the Knee Joint of the Musculoskeletal Leg

    Directory of Open Access Journals (Sweden)

    Jingtao Lei

    2017-03-01

    Full Text Available Pneumatic artificial muscles (PAMs have properties similar to biological muscle and are widely used in robotics as actuators. A musculoskeletal leg mechanism driven by PAMs is presented in this paper. The joint stiffness of the musculoskeletal bionic leg for jumping movement needs to be analysed. The synchronous control on the position and stiffness of the joint is important to improve the flexibility of leg. The accurate force model of PAM is the foundation to achieving better control and dynamic jumping performance. The experimental platform of PAM is conducted, and the static equal pressure experiments are performed to obtain the PAM force model. According to the testing data, parameter identification method is adopted to determine the force model of PAM. A simulation on the position and stiffness control of the knee joint is performed, and the simulation results show the effectiveness of the presented method.

  12. Are substrate use during exercise and mitochondrial respiratory capacity decreased in arm and leg muscle in type 2 diabetes?

    DEFF Research Database (Denmark)

    Larsen, Steen; Ara, I; Rabøl, R

    2009-01-01

    AIM/HYPOTHESIS: The aim of the study was to investigate mitochondrial function, fibre type distribution and substrate oxidation in arm and leg muscle during exercise in patients with type 2 diabetes and in obese and lean controls. METHODS: Indirect calorimetry was used to calculate fat and carboh...

  13. The minimum sit-to-stand height test: reliability, responsiveness and relationship to leg muscle strength.

    Science.gov (United States)

    Schurr, Karl; Sherrington, Catherine; Wallbank, Geraldine; Pamphlett, Patricia; Olivetti, Lynette

    2012-07-01

    To determine the reliability of the minimum sit-to-stand height test, its responsiveness and its relationship to leg muscle strength among rehabilitation unit inpatients and outpatients. Reliability study using two measurers and two test occasions. Secondary analysis of data from two clinical trials. Inpatient and outpatient rehabilitation services in three public hospitals. Eighteen hospital patients and five others participated in the reliability study. Seventy-two rehabilitation unit inpatients and 80 outpatients participated in the clinical trials. The minimum sit-to-stand height test was assessed using a standard procedure. For the reliability study, a second tester repeated the minimum sit-to-stand height test on the same day. In the inpatient clinical trial the measures were repeated two weeks later. In the outpatient trial the measures were repeated five weeks later. Knee extensor muscle strength was assessed in the clinical trials using a hand-held dynamometer. The reliability for the minimum sit-to-stand height test was excellent (intraclass correlation coefficient (ICC) 0.91, 95% confidence interval (CI) 0.81-0.96). The standard error of measurement was 34 mm. Responsiveness was moderate in the inpatient trial (effect size: 0.53) but small in the outpatient trial (effect size: 0.16). A small proportion (8-17%) of variability in minimum sit-to-stand height test was explained by knee extensor muscle strength. The minimum sit-to-stand height test has excellent reliability and moderate responsiveness in an inpatient rehabilitation setting. Responsiveness in an outpatient rehabilitation setting requires further investigation. Performance is influenced by factors other than knee extensor muscle strength.

  14. Leg to leg bioelectrical impedance analysis of percentage fat mass in obese patients-Can it tell us more than we already know?

    Science.gov (United States)

    Dixon, John B; Bhasker, Aparna G; Lambert, Gavin W; Lakdawala, Muffazal

    2016-08-01

    Bioelectrical impedance analysis (BIA) is well tolerated, inexpensive, and readily available, but can it be used to detect with clinical precision aberrant changes in the proportion of fat mass to fat-free mass during weight loss? To assess the variance in percentage body fat mass explained by the readily available inputs and assess residual variance provided by leg-to-leg BIA scales. Using cross-sectional data from a cohort of 665 patients of Indian ethnicity presenting for bariatric surgery, we examine the determinants of percentage body fat as provided by leg-to-leg output from Tanita SC-330 BIA scales. Four input factors-sex, weight, height, and age-contributed to provide 92% and 95% explanation in output variance for percentage fat mass (%FM) and actual fat mass, respectively, in 665 patients. Body mass index alone explained 89% and 81% of variance in %FM output for women and men, respectively. Neither weight distribution, as indicated by waist and hip circumference or waist to hip ratio, nor plasma lipids or markers of glucose metabolism contributed additional variance in %FM when controlled for the 4 key inputs. Simple, known input variables dominate the leg-to-leg BIA output of %FM, and this may compromise the detection of aberrant changes in %FM and fat-free mass with substantial weight loss. For clinical research, validated methods not largely dependent on known inputs should be used for evaluating changes in body composition after substantial weight loss. Copyright © 2016 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.

  15. Effects of unilateral leg muscle fatigue on balance control in perturbed and unperturbed gait in healthy elderly.

    Science.gov (United States)

    Toebes, Marcel J P; Hoozemans, Marco J M; Dekker, Joost; van Dieën, Jaap H

    2014-01-01

    This study assessed effects of unilateral leg muscle fatigue (ULMF) on balance control in gait during the stance and swing phases of the fatigued leg in healthy elderly, to test the assumption that leg muscle strength limits balance control during the stance-phase. Ten subjects (aged 63.4, SD 5.5 years) walked on a treadmill in 4 conditions: unperturbed unfatigued, unperturbed fatigued, perturbed unfatigued, and perturbed fatigued. The perturbations were lateral trunk pulls just before contralateral heel contact. ULMF was evoked by unilateral squat exercise until task failure. Isometric knee extension strength was measured to verify the presence of muscle fatigue. Between-stride standard deviations and Lyapunov exponents of trunk kinematics were used as indicators of balance control. Required perturbation force and the deviation of trunk kinematics from unperturbed gait were used to assess perturbation responses. Knee extension strength decreased considerably (17.3% SD 8.6%) as a result ULMF. ULMF did not affect steady-state gait balance. Less force was required to perturb subjects when the fatigued leg was in the stance-phase compared to the swing-phase. Subjects showed a faster return to the unperturbed gait pattern in the fatigued than in the unfatigued condition, after perturbations in swing and stance of the fatigued leg. The results of this study are not in line with the hypothesized effects of leg muscle fatigue on balance in gait. The healthy elderly subjects were able to cope with substantial ULMF during steady-state gait and demonstrated faster balance recovery after laterally directed mechanical perturbations in the fatigued than in the unfatigued condition. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Quantification of muscle oxygenation and flow of healthy volunteers during cuff occlusion of arm and leg flexor muscles and plantar flexion exercise

    Science.gov (United States)

    Durduran, Turgut; Yu, Guoqiang; Zhou, Chao; Lech, Gwen; Chance, Britton; Yodh, Arjun G.

    2003-07-01

    A hybrid instrument combining near infrared and diffuse correlation spectroscopies was used to measure muscle oxygenation and blood flow dynamics during cuff occlusion and ischemia. Measurements were done on six healthy subjects on their arm and leg flexor muscles. Hemodynamic response was characterized for blood oxygen saturation, total hemoglobin concenration and relative blood flow speed. The characterization allowed us to define the normal response range as well as showing the feasibility of using a hybrid instrument for dynamic measurements.

  17. Metabolic alterations caused by suspension hypokinesia in leg muscles of rats

    Science.gov (United States)

    Tischler, M. E.

    1984-01-01

    Metabolic changes on hypokinetic rats were measured. Two groups of animals were studied: (1) weight bearing control which were tail casted but allowed to walk on all four limbs, and (2) hypokinetic with no load bearing of the hindlimbs. The control and hypokinetic rats gained weight at a steady and similar rate over 6 days. Hypokinesia for 6 days led to significantly lower relative weights of the soleus, gastrocnemius and plantaris muscles. Hypokinesia did not effect the relative mass of the anterior tibialis or extensor digitorum longus (EDL) muscles.

  18. Test-retest reliability of maximal leg muscle power and functional performance measures in patients with severe osteoarthritis (OA)

    DEFF Research Database (Denmark)

    Villadsen, Allan; Roos, Ewa M.; Overgaard, Søren

    Abstract : Purpose To evaluate the reliability of single-joint and multi-joint maximal leg muscle power and functional performance measures in patients with severe OA. Background Muscle power, taking both strength and velocity into account, is a more functional measure of lower extremity muscle...... and scheduled for unilateral total hip (n=9) or knee (n=11) replacement. Patients underwent a test battery on two occasions separated by approximately one week (range 7 to 11 days). Muscle power was measured using: 1. A linear encoder, unilateral lower limb isolated single-joint dynamic movement, e.g. knee...... activity compared with the traditionally used isometric and/or isokinetic muscle strength. More functional measures are preferred to determine muscle function and as outcomes in exercise studies in patients with OA. Methods Subjects: 20 patients (mean age 68.7±7.2, BMI 29.0±3.9) diagnosed with severe OA...

  19. Age-related changes in the effects of strength training on lower leg muscles in healthy individuals measured using MRI.

    Science.gov (United States)

    Psatha, Maria; Wu, Zhiqing; Gammie, Fiona; Ratkevicius, Aivaras; Wackerhage, Henning; Redpath, Thomas W; Gilbert, Fiona J; Meakin, Judith R; Aspden, Richard M

    2017-01-01

    We previously measured the rate of regaining muscle strength during rehabilitation of lower leg muscles in patients following lower leg casting. Our primary aim in this study was to measure the rate of gain of strength in healthy individuals undergoing a similar training regime. Our secondary aim was to test the ability of MRI to provide a biomarker for muscle function. Men and women were recruited in three age groups: 20-30, 50-65 and over 70 years. Their response to resistance training of the right lower leg twice a week for 8 weeks was monitored using a dynamometer and MRI of tibialis anterior, soleus and gastrocnemius muscles at 2 weekly intervals to measure muscle size (anatomical cross-sectional area ( ACSA )) and quality ( T 2 relaxation). Forty-four volunteers completed the study. Baseline strength declined with age. Training had no effect in middle-aged females or in elderly men in dorsiflexion. Other groups significantly increased both plantarflexion and dorsiflexion strength at rates up to 5.5 N m week -1 in young females in plantarflexion and 1.25 N m week -1 in young males in dorsiflexion. No changes were observed in ACSA or T 2 in any age group in any muscle. Exercise training improves muscle strength in males at all ages except the elderly in dorsiflexion. Responses in females were less clear with variation across age and muscle groups. These results were not reflected in simple MRI measures that do not, therefore, provide a good biomarker for muscle atrophy or the efficacy of rehabilitation.

  20. Relation between systemic inflammatory markers, peripheral muscle mass, and strength in limb muscles in stable COPD patients

    Directory of Open Access Journals (Sweden)

    Ferrari R

    2015-08-01

    Full Text Available Renata Ferrari,1 Laura MO Caram,1 Marcia M Faganello,2 Fernanda F Sanchez,3 Suzana E Tanni,1 Irma Godoy1 1Botucatu Medical School, Department of Internal Medicine, Pneumology Area, Botucatu, São Paulo, 2Paulista State University, Department of Physiotherapy and Occupational Therapy, Marilia, São Paulo, 3Federal University of Amazonas, Department of Physiotherapy, Manaus, Amazonas, Brazil Abstract: The aim of this study was to investigate the association between systemic inflammatory mediators and peripheral muscle mass and strength in COPD patients. Fifty-five patients (69% male; age: 64±9 years with mild/very severe COPD (defined as forced expiratory volume in the first second [FEV1] =54%±23% were evaluated. We evaluated serum concentrations of IL-8, CRP, and TNF-α. Peripheral muscle mass was evaluated by computerized tomography (CT; midthigh cross-sectional muscle area (MTCSA and midarm cross-sectional muscle area (MACSA were obtained. Quadriceps, triceps, and biceps strength were assessed through the determination of the one-repetition maximum. The multiple regression results, adjusted for age, sex, and FEV1%, showed positive significant association between MTCSA and leg extension (0.35 [0.16, 0.55]; P=0.001, between MACSA and triceps pulley (0.45 [0.31, 0.58]; P=0.001, and between MACSA and biceps curl (0.34 [0.22, 0.47]; P=0.001. Plasma TNF-α was negatively associated with leg extension (-3.09 [-5.99, -0.18]; P=0.04 and triceps pulley (-1.31 [-2.35, -0.28]; P=0.01, while plasma CRP presented negative association with biceps curl (-0.06 [-0.11, -0.01]; P=0.02. Our results showed negative association between peripheral muscle mass (evaluated by CT and muscle strength and that systemic inflammation has a negative influence in the strength of specific groups of muscles in individuals with stable COPD. This is the first study showing association between systemic inflammatory markers and strength in upper limb muscles. Keywords

  1. Effects of bodyweight-based exercise training on muscle functions of leg multi-joint movement in elderly individuals.

    Science.gov (United States)

    Yamauchi, Junichiro; Nakayama, Satoshi; Ishii, Naokata

    2009-09-01

    Because demands of functional exercise training with using own bodyweight for elderly individuals were increasing, the present study investigated the effects of bodyweight-based exercise training on muscle functions of leg multi-joint movements in elderly individuals. Twenty-seven untrained healthy elderly individuals (mean +/- standard deviation, 66.0 +/- 5.7 years) completed the training program for 10 months. The exercise program consisted mainly of exercises for large leg muscle groups without using external weight, performing 10-50 repetitions and 1-3 sets for each exercise. Before and after the training period, force-velocity relations of knee-hip extension movements were measured with a servo-controlled dynamometer and the maximum force (Fmax), velocity (Vmax) and power (Pmax) were determined. After the training, Fmax and Pmax increased and these increases represented 15% (P elderly individuals; however, the initial training status is important for progressive increases in muscle force.

  2. Per meal dose and frequency of protein consumption is associated with lean mass and muscle performance.

    Science.gov (United States)

    Loenneke, Jeremy P; Loprinzi, Paul D; Murphy, Caoileann H; Phillips, Stuart M

    2016-12-01

    It has been hypothesized that for older adults evenly distributing consumption of protein at 30-40 g per meal throughout the day may result in more favorable retention of lean mass and muscular strength. Such a thesis has not, to our knowledge, been tested outside of short-term studies or acute measures of muscle protein synthesis. To examine whether the number of times an individual consumed a minimum of 30 g of protein at a meal is associated with leg lean mass and knee extensor strength. Data from the 1999-2002 NHANES were used, with 1081 adults (50-85 y) constituting the analytic sample. A "multiple pass" 24-h dietary interview format was used to collect detailed information about the participants' dietary intake. Knee extensor strength was assessed objectively using the Kin Com MP dynamometer. Leg lean mass was estimated from whole-body dual-energy X-ray absorptiometry (DXA) scans. Participants with 1 vs. 0 (β adjusted  = 23.6, p = 0.002) and 2 vs. 0 (β adjusted  = 51.1, p = 0.001) meals of ≥30 g protein/meal had greater strength and leg lean mass (1 vs. 0, β adjusted  = 1160, p frequency with leg lean mass and strength plateaued at ∼45 g protein/meal for those consuming 2 vs. 0 meals above the evaluated protein/meal threshold. However, for those with only 1 meal at or above the evaluated threshold, the response plateaued at 30 g/meal. Leg lean mass mediated the relationship between protein frequency and strength, with the proportion of the total effect mediated being 64%. We found that more frequent consumption of meals containing between 30 and 45 g protein/meal produced the greatest association with leg lean mass and strength. Thus, the consumption of 1-2 daily meals with protein content from 30 to 45 g may be an important strategy for increasing and/or maintaining lean body mass and muscle strength with aging. Copyright © 2016 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  3. N-of-1 trials of quinine efficacy in skeletal muscle cramps of the leg

    Science.gov (United States)

    Woodfield, Rachel; Goodyear-Smith, Felicity; Arroll, Bruce

    2005-01-01

    Background Skeletal muscle cramps affect over a third of the ambulatory elderly population. Quinine is the established treatment, but there are safety concerns, and evidence for efficacy is conflicting. A recent meta-analysis established a small advantage for quinine, but identified the need for additional studies. N-of-1 trials compare two treatments, in a randomised, double-blind, multiple crossover study on a patient-by-patient basis. They have been used to compare treatments in osteoarthritis and may be suitable for determining the individual efficacy of quinine. Aim To establish efficacy and safety of quinine sulphate use for the treatment of leg-muscle cramp. Design of study Double-blind, randomised series of n-of-1 controlled trials of quinine versus placebo for muscle cramps. Setting New Zealand general practices. Method The participants were 13 general practice patients (six males; seven females; median age = 75 years) already prescribed quinine. Following a 2-week washout, each patient received three 4-week treatment blocks of quinine sulphate and matched placebo capsules with an individual, randomised crossover design. The main outcome measures were: patient diaries of cramp occurrence, duration and severity; capsule counts; and blood quinine levels in the final treatment block. Results Ten patients completed the trial. Three patients were identified for whom quinine was clearly beneficial (P<0.05), six showed non-significant benefit and one showed no benefit. All patients elected to continue quinine post-study. Conclusion Series of n-of-1 studies differentiated patients whom quinine had statistically significant effects; those with trend towards effectiveness; those for whom quinine was probably not effective. Ideally n-of-1 trial should be performed when a patient is commenced on quinine. More cycles in n-of-1 studies of quinine may address issues of statistical power. PMID:15808032

  4. Does intermittent pneumatic leg compression enhance muscle recovery after strenuous eccentric exercise?

    Science.gov (United States)

    Cochrane, D J; Booker, H R; Mundel, T; Barnes, M J

    2013-11-01

    Intermittent pneumatic compression (IPC) has gained rapid popularity as a post-exercise recovery modality. Despite its widespread use and anecdotal claims for enhancing muscle recovery there is no scientific evidence to support its use. 10 healthy, active males performed a strenuous bout of eccentric exercise (3 sets of 100 repetitions) followed by IPC treatment or control performed immediately after exercise and at 24 and 48 h post-exercise. Muscular performance measurements were taken prior to exercise and 24, 48 and 72 h post-exercise and included single-leg vertical jump (VJ) and peak and average isometric [knee angle 75º] (ISO), concentric (CON) and eccentric (ECC) contractions performed at slow (30° · s⁻¹) and fast (180° · s⁻¹) velocities. Plasma creatine kinase (CK) samples were taken at pre- and post-exercise 24, 48 and 72 h. Strenuous eccentric exercise resulted in a significant decrease in peak ISO, peak and average CON (30° · s⁻¹) at 24 h compared to pre-exercise for both IPC and control, however VJ performance remained unchanged. There were no significant differences between conditions (IPC and control) or condition-time interactions for any of the contraction types (ISO, CON, ECC) or velocities (CON, ECC 30° · s⁻¹ and 180° · s⁻¹). However, CK was significantly elevated at 24 h compared to pre-exercise in both conditions (IPC and control). IPC did not attenuate muscle force loss following a bout of strenuous eccentric exercise in comparison to a control. While IPC has been used in the clinical setting to treat pathologic conditions, the parameters used to treat muscle damage following strenuous exercise in healthy participants are likely to be very different than those used to treat pathologic conditions. © Georg Thieme Verlag KG Stuttgart · New York.

  5. Maintained peak leg and pulmonary VO2 despite substantial reduction in muscle mitochondrial capacity

    DEFF Research Database (Denmark)

    Boushel, Robert; Gnaiger, E.; Larsen, F. J.

    2015-01-01

    of the vastus lateralis in healthy volunteers (7 male, 2 female) before and after 42 days of skiing at 60% HR max. Peak pulmonary VO2 (3.52 ± 0.18 L.min-1 pre vs 3.52 ± 0.19 post) and VO2 across the leg (2.8 ± 0.4L.min-1 pre vs 3.0 ± 0.2 post) were unchanged after the ski journey. Peak leg O2 delivery (3.6 ± 0...... at a higher mitochondrial p50. These findings support the concept that muscle mitochondrial respiration is submaximal at VO2max , and that mitochondrial volume can be downregulated by chronic energy demand.......We recently reported the circulatory and muscle oxidative capacities of the arm after prolonged low-intensity skiing in the arctic (Boushel et al., 2014). In the present study, leg VO2 was measured by the Fick method during leg cycling while muscle mitochondrial capacity was examined on a biopsy...

  6. Integrated expression analysis of muscle hypertrophy identifies Asb2 as a negative regulator of muscle mass

    Science.gov (United States)

    Davey, Jonathan R.; Watt, Kevin I.; Parker, Benjamin L.; Chaudhuri, Rima; Ryall, James G.; Cunningham, Louise; Qian, Hongwei; Sartorelli, Vittorio; Chamberlain, Jeffrey; James, David E.

    2016-01-01

    The transforming growth factor-β (TGF-β) signaling network is a critical regulator of skeletal muscle mass and function and, thus, is an attractive therapeutic target for combating muscle disease, but the underlying mechanisms of action remain undetermined. We report that follistatin-based interventions (which modulate TGF-β network activity) can promote muscle hypertrophy that ameliorates aging-associated muscle wasting. However, the muscles of old sarcopenic mice demonstrate reduced response to follistatin compared with healthy young-adult musculature. Quantitative proteomic and transcriptomic analyses of young-adult muscles identified a transcription/translation signature elicited by follistatin exposure, which included repression of ankyrin repeat and SOCS box protein 2 (Asb2). Increasing expression of ASB2 reduced muscle mass, thereby demonstrating that Asb2 is a TGF-β network–responsive negative regulator of muscle mass. In contrast to young-adult muscles, sarcopenic muscles do not exhibit reduced ASB2 abundance with follistatin exposure. Moreover, preventing repression of ASB2 in young-adult muscles diminished follistatin-induced muscle hypertrophy. These findings provide insight into the program of transcription and translation events governing follistatin-mediated adaptation of skeletal muscle attributes and identify Asb2 as a regulator of muscle mass implicated in the potential mechanistic dysfunction between follistatin-mediated muscle growth in young and old muscles. PMID:27182554

  7. Foot muscle morphology is related to center of pressure sway and control mechanisms during single-leg standing.

    Science.gov (United States)

    Zhang, Xianyi; Schütte, Kurt Heinrich; Vanwanseele, Benedicte

    2017-09-01

    Maintaining balance is vitally important in everyday life. Investigating the effects of individual foot muscle morphology on balance may provide insights into neuromuscular balance control mechanisms. This study aimed to examine the correlation between the morphology of foot muscles and balance performance during single-leg standing. Twenty-eight recreational runners were recruited in this study. An ultrasound device was used to measure the thickness and cross-sectional area of three intrinsic foot muscles (abductor hallucis, flexor digitorum brevis and quadratus plantae) and peroneus muscles. Participants were required to perform 30s of single-leg standing for three trials on a force plate, which was used to record the center of pressure (COP). The standard deviation of the amplitude and ellipse area of the COP were calculated. In addition, stabilogram diffusion analysis (SDA) was performed on COP data. Pearson correlation coefficients were computed to examine the correlation between foot muscle morphology and traditional COP parameters as well as with SDA parameters. Our results showed that larger abductor hallucis correlated to smaller COP sway, while larger peroneus muscles correlated to larger COP sway during single-leg standing. Larger abductor hallucis also benefited open-loop dynamic stability, as well as supported a more efficient transfer from open-loop to closed loop control mechanisms. These results suggest that the morphology of foot muscles plays an important role in balance performance, and that strengthening the intrinsic foot muscles may be an effective way to improve balance. Copyright © 2017. Published by Elsevier B.V.

  8. Local heat application to the leg reduces muscle sympathetic nerve activity in human.

    Science.gov (United States)

    Takahashi, Noriyo; Nakamura, Takeshi; Kanno, Nami; Kimura, Kenichi; Toge, Yasushi; Lee, Kyu-Ha; Tajima, Fumihiro

    2011-09-01

    The study was designed to assess the effects of local heat (LH) application on postganglionic muscle sympathetic nerve activity (MSNA) measured by microneurography in healthy men. In the first protocol, MSNA of the left peroneal nerve, blood pressure (BP), heart rate (HR), and skin temperature of the shin (TSK) were recorded in nine men. In the second protocol, leg blood flow (LBF) was measured in the same subjects by strain-gauge plethysmography. In both protocols, after 10 min of rest in the supine position, a heated hydrocollator pack was applied to the shin and anterior foot for 15 min and recovery was monitored over a period of 20 min. TSK gradually increased from 31.7 ± 0.1 to 41.9 ± 0.5°C (mean ± SEM) during LH. No subject complained of pain, and BP and HR remained constant. The MSNA burst rate (16.1 ± 2.1 beats/min) during the control period decreased significantly (P < 0.05) to 72.0 ± 2.3% during LH. Total MSNA also decreased to 59.2 ± 2.6% (P < 0.05) during LH, but both immediately returned to baseline at recovery. In contrast, LBF in the left leg significantly and immediately increased (P < 0.05) after LH application and remained significantly elevated until the end of the recovery period. These results suggest that: (1) LH application significantly attenuates MSNA without any changes in HR and BP. (2) Other factors in addition to MSNA seem to control regional blood flow in the lower extremity during LH.

  9. The effects of performing a one-legged bridge with hip abduction and use of a sling on trunk and lower extremity muscle activation in healthy adults.

    Science.gov (United States)

    Choi, Kyuju; Bak, Jongwoo; Cho, Minkwon; Chung, Yijung

    2016-09-01

    [Purpose] This study investigated the changes in the muscle activities of the trunk and lower limbs of healthy adults during a one-legged bridge exercise using a sling, and with the addition of hip abduction. [Subjects and Methods] Twenty-seven healthy individuals participated in this study (14 males and 13 females). The participants were instructed to perform the bridge exercises under five different conditions. Trunk and lower limb muscle activation of the erector spinae (ES), external oblique (EO), gluteus maximus (GM), and biceps femoris (BF) was measured using surface electromyography. Data analysis was performed using the mean scores of three trials performed under each condition. [Results] There was a significant increase in bilateral EO and contralateral GM with the one-legged bridge compared with the one-legged bridge with sling exercise. Muscle activation of the ipsilateral GM and BF was significantly less during the one-legged bridge exercise compared to the one-legged bridge with sling exercise, and was significantly greater during the one-legged bridge with hip abduction compared to the one-legged bridge exercise. The muscle activation of the contralateral GM and BF was significantly greater with the one-legged bridge with hip abduction compared to the general bridge exercise. [Conclusion] With the one-legged bridge with hip abduction, the ipsilateral EO, GM and BF muscle activities were significantly greater than those of the one-legged bridge exercise. The muscle activation of all trunk and contralateral lower extremity muscles increased with the bridge with sling exercises compared with general bridge exercises.

  10. Placebo effect of an inert gel on experimentally induced leg muscle pain

    Directory of Open Access Journals (Sweden)

    James G Hopker

    2010-11-01

    Full Text Available James G Hopker1, Abigail J Foad2, Christopher J Beedie2, Damian A Coleman2, Geoffrey Leach11Centre for Sports Studies, University of Kent, Chatham, Kent, UK; 2Department of Sports Science, Tourism and Leisure, Canterbury Christ Church University, Canterbury, Kent, UKPurpose: This study examined the therapeutic effects of an inert placebo gel on experimentally induced muscle pain in a sports therapy setting. It aimed to investigate the degree to which conditioned analgesia, coupled with an expectation of intervention, was a factor in subsequent analgesia.Methods: Participants were sixteen male and eight female sports therapy students at a UK University. With institutional ethics board approval and following informed consent procedures, each was exposed to pain stimulus in the lower leg in five conditions, ie, conditioning, prebaseline, experimental (two placebo gel applications, and postbaseline. In conditioning trials, participants identified a level of pain stimulus equivalent to a perceived pain rating of 6/10. An inert placebo gel was then applied to the site with the explicit instruction that it was an analgesic. Participants were re-exposed to the pain stimulus, the level of which, without their knowledge, had been decreased, creating the impression of an analgesic effect resulting from the gel. In experimental conditions, the placebo gel was applied and the level of pain stimulus required to elicit a pain rating of 6/10 recorded.Results: Following application of the placebo gel, the level of pain stimulus required to elicit a pain rating of 6/10 increased by 8.2%. Application of the placebo gel significantly decreased participant’s perceptions of muscle pain (P = 0.001.Conclusion: Subjects’ experience and expectation of pain reduction may be major factors in the therapeutic process. These factors should be considered in the sports therapeutic environment.Keywords: conditioning, expectation, perception, positive belief, sports therapy

  11. Relation between body mass index percentile and muscle strength ...

    African Journals Online (AJOL)

    Noha Abdel Kader Abdel Kader Hasan

    2016-02-01

    Feb 1, 2016 ... a positive correlation between muscle strength and body mass index percentile while muscle endur- ance time had a negative correlation with it. Conclusion: The study shows that the BMI of children had a positive correlation with the muscle ... lar force in a specific movement pattern at definite velocity.

  12. Analysis of Foot Slippage Effects on an Actuated Spring-Mass Model of Dynamic Legged Locomotion

    Directory of Open Access Journals (Sweden)

    Yizhar Or

    2016-04-01

    Full Text Available The classical model of spring-loaded inverted pendulum (SLIP and its extensions have been widely accepted as a simple description of dynamic legged locomotion at various scales in humans, legged robots and animals. Similar to the majority of models in the literature, the SLIP model assumes ideal sticking contact of the foot. However, there are practical scenarios of low ground friction that causes foot slippage, which can have a significant influence on dynamic behaviour. In this work, an extension of the SLIP model with two masses and torque actuation is considered, which accounts for possible slippage under Coulomb's friction law. The hybrid dynamics of this model is formulated and numerical simulations under representative parameter values reveal several types of stable periodic solutions with stick-slip transitions. Remarkably, it is found that slippage due to low friction can sometimes increase average speed and improve energetic efficiency by significantly reducing the mechanical cost of transport.

  13. Optimal Resistive Forces for Maximizing the Reliability of Leg Muscles' Capacities Tested on a Cycle Ergometer.

    Science.gov (United States)

    García-Ramos, Amador; Torrejón, Alejandro; Morales-Artacho, Antonio J; Pérez-Castilla, Alejandro; Jaric, Slobodan

    2018-02-01

    This study determined the optimal resistive forces for testing muscle capacities through the standard cycle ergometer test (1 resistive force applied) and a recently developed 2-point method (2 resistive forces used for force-velocity modelling). Twenty-six men were tested twice on maximal sprints performed on a leg cycle ergometer against 5 flywheel resistive forces (R1-R5). The reliability of the cadence and maximum power measured against the 5 individual resistive forces, as well as the reliability of the force-velocity relationship parameters obtained from the selected 2-point methods (R1-R2, R1-R3, R1-R4, and R1-R5), were compared. The reliability of outcomes obtained from individual resistive forces was high except for R5. As a consequence, the combination of R1 (≈175 rpm) and R4 (≈110 rpm) provided the most reliable 2-point method (CV: 1.46%-4.04%; ICC: 0.89-0.96). Although the reliability of power capacity was similar for the R1-R4 2-point method (CV: 3.18%; ICC: 0.96) and the standard test (CV: 3.31%; ICC: 0.95), the 2-point method should be recommended because it also reveals maximum force and velocity capacities. Finally, we conclude that the 2-point method in cycling should be based on 2 distant resistive forces, but avoiding cadences below 110 rpm.

  14. Relationships Between Lower-Body Muscle Structure and, Lower-Body Strength, Explosiveness and Eccentric Leg Stiffness in Adolescent Athletes

    Directory of Open Access Journals (Sweden)

    Josh L. Secomb, Sophia Nimphius, Oliver R.L. Farley, Lina E. Lundgren, Tai T. Tran, Jeremy M. Sheppard

    2015-12-01

    Full Text Available The purpose of the present study was to determine whether any relationships were present between lower-body muscle structure and, lower-body strength, variables measured during a countermovement jump (CMJ and squat jump (SJ, and eccentric leg stiffness, in adolescent athletes. Thirty junior male (n = 23 and female (n = 7 surfing athletes (14.8 ± 1.7 y; 1.63 ± 0.09 m; 54.8 ± 12.1 kg undertook lower-body muscle structure assessment with ultrasonography and performed a; CMJ, SJ and an isometric mid-thigh pull (IMTP. In addition, eccentric leg stiffness was calculated from variables of the CMJ and IMTP. Moderate to very large relationships (r = 0.46-0.73 were identified between the thickness of the vastus lateralis (VL and lateral gastrocnemius (LG muscles, and VL pennation angle and; peak force (PF in the CMJ, SJ and IMTP. Additionally, moderate to large relationships (r = 0.37-0.59 were found between eccentric leg stiffness and; VL and LG thickness, VL pennation angle, and LG fascicle length, with a large relationship (r = 0.59 also present with IMTP PF. These results suggest that greater thickness of the VL and LG were related to improved maximal dynamic and isometric strength, likely due to increased hypertrophy of the extensor muscles. Furthermore, this increased thickness was related to greater eccentric leg stiffness, as the associated enhanced lower-body strength likely allowed for greater neuromuscular activation, and hence less compliance, during a stretch-shortening cycle.

  15. Muscle sympathetic nerve responses to passive and active one-legged cycling: insights into the contributions of central command.

    Science.gov (United States)

    Doherty, Connor J; Incognito, Anthony V; Notay, Karambir; Burns, Matthew J; Slysz, Joshua T; Seed, Jeremy D; Nardone, Massimo; Burr, Jamie F; Millar, Philip J

    2018-01-01

    The contribution of central command to the peripheral vasoconstrictor response during exercise has been investigated using primarily handgrip exercise. The purpose of the present study was to compare muscle sympathetic nerve activity (MSNA) responses during passive (involuntary) and active (voluntary) zero-load cycling to gain insights into the effects of central command on sympathetic outflow during dynamic exercise. Hemodynamic measurements and contralateral leg MSNA (microneurography) data were collected in 18 young healthy participants at rest and during 2 min of passive and active zero-load one-legged cycling. Arterial baroreflex control of MSNA burst occurrence and burst area were calculated separately in the time domain. Blood pressure and stroke volume increased during exercise ( P cycling ( P > 0.05). In contrast, heart rate, cardiac output, and total vascular conductance were greater during the first and second minute of active cycling ( P cycling ( P 0.05). Reductions in total MSNA were attenuated during the first ( P cycling, in concert with increased MSNA burst amplitude ( P = 0.02 and P = 0.005, respectively). The sensitivity of arterial baroreflex control of MSNA burst occurrence was lower during active than passive cycling ( P = 0.01), while control of MSNA burst strength was unchanged ( P > 0.05). These results suggest that central feedforward mechanisms are involved primarily in modulating the strength, but not the occurrence, of a sympathetic burst during low-intensity dynamic leg exercise. NEW & NOTEWORTHY Muscle sympathetic nerve activity burst frequency decreased equally during passive and active cycling, but reductions in total muscle sympathetic nerve activity were attenuated during active cycling. These results suggest that central command primarily regulates the strength, not the occurrence, of a muscle sympathetic burst during low-intensity dynamic leg exercise.

  16. Near-Infrared Spectroscopic Measurement of the Effect of Leg Dominance on Muscle Oxygen Saturation During Cycling

    Science.gov (United States)

    Ellerby, Gwenn E. C.; Lee, Stuart M. C.; Paunescu, Lelia Adelina; Pereira, Chelsea; Smith, Charles P.; Soller, Babs R.

    2011-01-01

    The effect of leg dominance on the symmetry of the biomechanics during cycling remains uncertain -- asymmetries have been observed in kinematics and kinetics, while symmetries were found in muscle activation. No studies have yet investigated the symmetry of muscle metabolism during cycling. Near-infrared spectroscopy (NIRS) provides a non-invasive method to investigate the metabolic responses of specific muscles during cycling. PURPOSE: To determine whether there was an effect of leg dominance on thigh muscle oxygen saturation (SmO2) during incrementally loaded submaximal cycling using NIRS. METHODS: Eight right leg dominant, untrained subjects (5 men, 3 women; 31+/-2 yrs; 168.6+/-1.0 cm; 67.2+/-1.8 kg, mean +/- SE) volunteered to participate. Spectra were collected bilaterally from the vastus lateralis (VL) during supine rest and cycling. SmO2 was calculated using previously published methods. Subjects pedaled at 65 rpm while resistance to pedaling was increased in 0.5 kp increments from 0.5 kp every 3 min until the subject reached 80% of age-predicted maximal heart rate. SmO2 was averaged over 3 min for each completed stage. A two-way ANOVA was performed to test for leg differences. A priori contrasts were used to compare work levels to rest. RESULTS: VL SmO2 was not different between the dominant and non-dominant legs at rest and during exercise (p=0.57). How SmO2 changed with workload was also not different between legs (p=0.32). SmO2 at 0.5 kp (60.3+/-4.0, p=0.12) and 1.0 kp (59.5+/-4.0, p=0.10) was not different from rest (69.1+/-4.0). SmO2 at 1.5 kp (55.4 4.0, p=0.02), 2.0 kp (55.7+/-5.0, p=0.04), and 2.5 kp (43.4+/-7.9, p=0.01) was significantly lower than rest. CONCLUSION: VL SmO2 during cycling is not different between dominant and non-dominant legs and decreases with moderate workload in untrained cyclists. Assuming blood flow is directed equally to both legs, similar levels of oxygen extraction (as indicated by SmO2) suggests the metabolic load of

  17. Magnetic Resonance Assessment of Hypertrophic and Pseudo-Hypertrophic Changes in Lower Leg Muscles of Boys with Duchenne Muscular Dystrophy and Their Relationship to Functional Measurements.

    Science.gov (United States)

    Vohra, Ravneet S; Lott, Donovan; Mathur, Sunita; Senesac, Claudia; Deol, Jasjit; Germain, Sean; Bendixen, Roxanna; Forbes, Sean C; Sweeney, H Lee; Walter, Glenn A; Vandenborne, Krista

    2015-01-01

    The primary objectives of this study were to evaluate contractile and non-contractile content of lower leg muscles of boys with Duchenne muscular dystrophy (DMD) and determine the relationships between non-contractile content and functional abilities. Lower leg muscles of thirty-two boys with DMD and sixteen age matched unaffected controls were imaged. Non-contractile content, contractile cross sectional area and non-contractile cross sectional area of lower leg muscles (tibialis anterior, extensor digitorum longus, peroneal, medial gastrocnemius and soleus) were assessed by magnetic resonance imaging (MRI). Muscle strength, timed functional tests and the Brooke lower extremity score were also assessed. Non-contractile content of lower leg muscles (peroneal, medial gastrocnemius, and soleus) was significantly greater than control group (p<0.05). Non-contractile content of lower leg muscles correlated with Brooke score (rs = 0.64-0.84) and 30 feet walk (rs = 0.66-0.80). Dorsiflexor (DF) and plantarflexor (PF) specific torque was significantly different between the groups. Overall, non-contractile content of the lower leg muscles was greater in DMD than controls. Furthermore, there was an age dependent increase in contractile content in the medial gastrocnemius of boys with DMD. The findings of this study suggest that T1 weighted MR images can be used to monitor disease progression and provide a quantitative estimate of contractile and non-contractile content of tissue in children with DMD.

  18. Magnetic Resonance Assessment of Hypertrophic and Pseudo-Hypertrophic Changes in Lower Leg Muscles of Boys with Duchenne Muscular Dystrophy and Their Relationship to Functional Measurements.

    Directory of Open Access Journals (Sweden)

    Ravneet S Vohra

    Full Text Available The primary objectives of this study were to evaluate contractile and non-contractile content of lower leg muscles of boys with Duchenne muscular dystrophy (DMD and determine the relationships between non-contractile content and functional abilities.Lower leg muscles of thirty-two boys with DMD and sixteen age matched unaffected controls were imaged. Non-contractile content, contractile cross sectional area and non-contractile cross sectional area of lower leg muscles (tibialis anterior, extensor digitorum longus, peroneal, medial gastrocnemius and soleus were assessed by magnetic resonance imaging (MRI. Muscle strength, timed functional tests and the Brooke lower extremity score were also assessed.Non-contractile content of lower leg muscles (peroneal, medial gastrocnemius, and soleus was significantly greater than control group (p<0.05. Non-contractile content of lower leg muscles correlated with Brooke score (rs = 0.64-0.84 and 30 feet walk (rs = 0.66-0.80. Dorsiflexor (DF and plantarflexor (PF specific torque was significantly different between the groups.Overall, non-contractile content of the lower leg muscles was greater in DMD than controls. Furthermore, there was an age dependent increase in contractile content in the medial gastrocnemius of boys with DMD. The findings of this study suggest that T1 weighted MR images can be used to monitor disease progression and provide a quantitative estimate of contractile and non-contractile content of tissue in children with DMD.

  19. Relationships Between Lower-Body Muscle Structure and, Lower-Body Strength, Explosiveness and Eccentric Leg Stiffness in Adolescent Athletes

    OpenAIRE

    Secomb, Josh L.; Nimphius, Sophia; Farley, Oliver R.L.; Lundgren, Lina E.; Tran, Tai T.; Sheppard, Jeremy M.

    2015-01-01

    The purpose of the present study was to determine whether any relationships were present between lower-body muscle structure and, lower-body strength, variables measured during a countermovement jump (CMJ) and squat jump (SJ), and eccentric leg stiffness, in adolescent athletes. Thirty junior male (n = 23) and female (n = 7) surfing athletes (14.8 ± 1.7 y; 1.63 ± 0.09 m; 54.8 ± 12.1 kg) undertook lower-body muscle structure assessment with ultrasonography and performed a; CMJ, SJ and an isome...

  20. Skeletal muscle mass adjusted by height correlated better with muscular functions than that adjusted by body weight in defining sarcopenia.

    Science.gov (United States)

    Han, Der-Sheng; Chang, Ke-Vin; Li, Chia-Ming; Lin, Yu-Hong; Kao, Tung-Wei; Tsai, Keh-Sung; Wang, Tyng-Grey; Yang, Wei-Shiung

    2016-01-20

    Sarcopenia, characterized by low muscle mass and function, results in frailty, comorbidities and mortality. However, its prevalence varies according to the different criteria used in its diagnosis. This cross-sectional study investigated the difference in the number of sarcopenia cases recorded by two different measurement methods of low muscle mass to determine which measurement was better. We recruited 878 (54.2% female) individuals aged over 65 years and obtained their body composition and functional parameters. Low muscle mass was defined as two standard deviations below either the mean height-adjusted (hSMI) or weight-adjusted (wSMI) muscle mass of a young reference group. The prevalence of sarcopenia was 6.7% vs. 0.4% (male/female) by hSMI, and 4.0% vs. 10.7% (male/female) by wSMI. The κ coefficients for these two criteria were 0.39 vs. 0.03 (male/female), and 0.17 in all subjects. Serum myostatin levels correlated positively with gait speed (r = 0.142, p = 0.007) after adjustment for gender. hSMI correlated with grip strength, cardiopulmonary endurance, leg endurance, gait speed, and flexibility. wSMI correlated with grip strength, leg endurance, gait speed, and flexibility. Since hSMI correlated more closely with grip strength and more muscular functions, we recommend hSMI in the diagnosis of low muscle mass.

  1. Application of segmental bioelectrical impedance spectroscopy to the assessment of skeletal muscle cell mass in elderly men.

    Science.gov (United States)

    Yamada, Yosuke; Matsuda, Kaori; Björkman, Mikko P; Kimura, Misaka

    2014-02-01

    It is important to assess not only the total skeletal muscle mass, but also the intracellular and extracellular compartments of skeletal muscle to examine the actual relationship between skeletal muscle mass and physical functions. Segmental bioelectrical impedance spectroscopy is a unique tool with which to assess intracellular and extracellular water in the limbs. The aim of the present study was to examine the application of segmental bioelectrical impedance spectroscopy to the assessment of skeletal muscle mass in the elderly. A total of 73 healthy elderly men and 20 elderly men requiring care and using an ambulatory day-care service of the public long-term care insurance system participated in the present study. The intracellular and extracellular water in the upper and lower legs were assessed by segmental bioelectrical impedance spectroscopy. The gait speed, grip strength and maximal isometric knee extension strength were measured. The elderly requiring care had significantly lower intracellular water than did healthy elderly in the upper and lower legs. A significant relative expansion of extracellular water against total water was observed in the elderly requiring care. Receiver operating characteristic curves showed that the area under the curve for the intracellular water index was similar to that for muscle strength in the discrimination of elderly requiring care. The elderly requiring care had a relative expansion of extracellular water in the legs, which could have masked actual muscle atrophy. Segmental bioelectrical impedance spectroscopy would be useful for the assessment of skeletal muscle cell mass and sarcopenia in the elderly. © 2014 Japan Geriatrics Society.

  2. Consequences of simulated car driving at constant high speed on the sensorimotor control of leg muscles and the braking response.

    Science.gov (United States)

    Jammes, Yves; Behr, Michel; Weber, Jean P; Berdah, Stephane

    2017-11-01

    Due to the increase in time spent seated in cars, there is a risk of fatigue of the leg muscles which adjust the force exerted on the accelerator pedal. Any change in their sensorimotor control could lengthen the response to emergency braking. Fourteen healthy male subjects (mean age: 42 ± 4 years) were explored. Before and after a 1-h driving trial at 120 km h -1 , we measured the braking response, the maximal leg extension and foot inversion forces, the tonic vibratory response (TVR) in gastrocnemius medialis (GM) and tibialis anterior (TA) muscles to explore the myotatic reflex, and the Hoffmann reflex (H-reflex). During driving, surface electromyograms (EMGs) of GM and TA were recorded and the ratio between high (H) and low (L) EMG energies allowed to evaluate the recruitment of high- and low-frequency motor unit discharges. During driving, the H/L ratio decreased in TA, whereas modest and often no significant H/L changes occurred in GM muscle. After driving, the maximal foot inversion force decreased (-19%), while the leg extension force did not vary. Reduced TVR amplitude (-29%) was measured in TA, but no H-reflex changes were noted. The braking reaction time was not modified after the driving trial. Driving at constant elevated speed reduced the myotatic reflex and the recruitment of motor units in TA muscle. The corresponding changes were rarely present in the GM muscle that plays a key role in the braking response, and this could explain the absence of a reduced braking reaction time. © 2016 Scandinavian Society of Clinical Physiology and Nuclear Medicine. Published by John Wiley & Sons Ltd.

  3. Timing of muscle response to a sudden leg perturbation: comparison between adolescents and adults with Down syndrome.

    Directory of Open Access Journals (Sweden)

    Maria Stella Valle

    Full Text Available Movement disturbances associated with Down syndrome reduce mechanical stability, worsening the execution of important tasks such as walking and upright standing. To compensate these deficits, persons with Down syndrome increase joint stability modulating the level of activation of single muscles or producing an agonist-antagonist co-activation. Such activations are also observed when a relaxed, extended leg is suddenly released and left to oscillate passively under the influence of gravity (Wartenberg test. In this case, the Rectus femoris of adults with Down syndrome displayed peaks of activation after the onset of the first leg flexion. With the aim to verify if these muscular reactions were acquired during the development time and to find evidences useful to give them a functional explanation, we used the Wartenberg test to compare the knee joint kinematics and the surface electromyography of the Rectus femoris and Biceps femoris caput longus between adolescents and adults with Down syndrome. During the first leg flexion, adolescents and adults showed single Rectus femoris activations while, a restricted number of participants exhibited agonist-antagonist co-activations. However, regardless the pattern of activation, adults initiated the muscle activity significantly later than adolescents. Although most of the mechanical parameters and the total movement variability were similar in the two groups, the onset of the Rectus femoris activation was well correlated with the time of the minimum acceleration variability. Thus, in adolescents the maximum mechanical stability occurred short after the onset of the leg fall, while adults reached their best joint stability late during the first flexion. These results suggest that between the adolescence and adulthood, persons with Down syndrome explore a temporal window to select an appropriate timing of muscle activation to overcome their inherent mechanical instability.

  4. Ultrasound measurement of the size of the anterior tibial muscle group: the effect of exercise and leg dominance

    LENUS (Irish Health Repository)

    McCreesh, Karen

    2011-09-13

    Abstract Background Knowledge of normal muscle characteristics is crucial in planning rehabilitation programmes for injured athletes. There is a high incidence of ankle and anterior tibial symptoms in football players, however little is known about the effect of limb dominance on the anterior tibial muscle group (ATMG). The purpose of this study was to assess the effect of limb dominance and sports-specific activity on ATMG thickness in Gaelic footballers and non-football playing controls using ultrasound measurements, and to compare results from transverse and longitudinal scans. Methods Bilateral ultrasound scans were taken to assess the ATMG size in 10 Gaelic footballers and 10 sedentary controls (age range 18-25 yrs), using a previously published protocol. Both transverse and longitudinal images were taken. Muscle thickness measurements were carried out blind to group and side of dominance, using the Image-J programme. Results Muscle thickness on the dominant leg was significantly greater than the non-dominant leg in the footballers with a mean difference of 7.3%, while there was no significant dominance effect in the controls (p < 0.05). There was no significant difference between the measurements from transverse or longitudinal scans. Conclusions A significant dominance effect exists in ATMG size in this group of Gaelic footballers, likely attributable to the kicking action involved in the sport. This should be taken into account when rehabilitating footballers with anterior tibial pathology. Ultrasound is a reliable tool to measure ATMG thickness, and measurement may be taken in transverse or longitudinal section.

  5. Bio-inspired swing leg control for spring-mass robots running on ground with unexpected height disturbance.

    Science.gov (United States)

    Vejdani, H R; Blum, Y; Daley, M A; Hurst, J W

    2013-12-01

    We proposed three swing leg control policies for spring-mass running robots, inspired by experimental data from our recent collaborative work on ground running birds. Previous investigations suggest that animals may prioritize injury avoidance and/or efficiency as their objective function during running rather than maintaining limit-cycle stability. Therefore, in this study we targeted structural capacity (maximum leg force to avoid damage) and efficiency as the main goals for our control policies, since these objective functions are crucial to reduce motor size and structure weight. Each proposed policy controls the leg angle as a function of time during flight phase such that its objective function during the subsequent stance phase is regulated. The three objective functions that are regulated in the control policies are (i) the leg peak force, (ii) the axial impulse, and (iii) the leg actuator work. It should be noted that each control policy regulates one single objective function. Surprisingly, all three swing leg control policies result in nearly identical subsequent stance phase dynamics. This implies that the implementation of any of the proposed control policies would satisfy both goals (damage avoidance and efficiency) at once. Furthermore, all three control policies require a surprisingly simple leg angle adjustment: leg retraction with constant angular acceleration.

  6. A dietary supplementation with leucine and antioxidants is capable to accelerate muscle mass recovery after immobilization in adult rats.

    Directory of Open Access Journals (Sweden)

    Isabelle Savary-Auzeloux

    Full Text Available Prolonged inactivity induces muscle loss due to an activation of proteolysis and decreased protein synthesis; the latter is also involved in the recovery of muscle mass. The aim of the present work was to explore the evolution of muscle mass and protein metabolism during immobilization and recovery and assess the effect of a nutritional strategy for counteracting muscle loss and facilitating recovery. Adult rats (6-8 months were subjected to unilateral hindlimb casting for 8 days (I0-I8 and then permitted to recover for 10 to 40 days (R10-R40. They were fed a Control or Experimental diet supplemented with antioxidants/polyphenols (AOX (I0 to I8, AOX and leucine (AOX + LEU (I8 to R15 and LEU alone (R15 to R40. Muscle mass, absolute protein synthesis rate and proteasome activities were measured in gastrocnemius muscle in casted and non-casted legs in post prandial (PP and post absorptive (PA states at each time point. Immobilized gastrocnemius protein content was similarly reduced (-37% in both diets compared to the non-casted leg. Muscle mass recovery was accelerated by the AOX and LEU supplementation (+6% AOX+LEU vs. Control, P<0.05 at R40 due to a higher protein synthesis both in PA and PP states (+23% and 31% respectively, Experimental vs. Control diets, P<0.05, R40 without difference in trypsin- and chymotrypsin-like activities between diets. Thus, this nutritional supplementation accelerated the recovery of muscle mass via a stimulation of protein synthesis throughout the entire day (in the PP and PA states and could be a promising strategy to be tested during recovery from bed rest in humans.

  7. The effects of muscle mass and muscle quality on cardio-metabolic risk in peripubertal girls: a longitudinal study from childhood to early adulthood.

    Science.gov (United States)

    Cheng, S; Wiklund, P

    2017-10-30

    Increased cardio-metabolic risk is well documented in children and adolescents with obesity and normal weight obesity (NWO). However, the associations of muscle mass and muscle quality with cardio-metabolic risk, independent of weight status from childhood to adulthood, has not been examined. A total of 236 girls were followed from pre-puberty to early adulthood. Fat mass (FM) and lean mass (LM) of the whole body were assessed by a dual-energy X-ray absorptiometry; muscle cross-sectional area (mCSA), muscle density (mDen; skeletal muscle fat content) of the lower leg by the peripheral quantitative computerized tomography; and blood glucose, insulin, triglycerides and high-density lipoprotein cholesterol by enzymatic photometric methods. Study participants were categorized based on body mass index (BMI) and percentage body fat (%BF) as overweight and/or obese (BMI⩾30 with %BF⩾30), normal weight obese (BMI 18.5-24.9 with %BF⩾30) and normal weight lean (BMI 18.5-24.9 with %BF cardio-metabolic risk score (r 2 =0.012, Pcardio-metabolic risk factors during pubertal growth after adjusting for measures of adiposity. Ectopic fat accumulation in the skeletal muscle and increased adiposity, particularly in the abdominal area in childhood, are significant contributors to increased cardio-metabolic risk in adulthood, irrespective of body weight status.International Journal of Obesity advance online publication, 28 November 2017; doi:10.1038/ijo.2017.267.

  8. Clinical effectiveness of protein and amino acid supplementation on building muscle mass in elderly people: a meta-analysis.

    Directory of Open Access Journals (Sweden)

    Zhe-rong Xu

    Full Text Available A major reason for the loss of mobility in elderly people is the gradual loss of lean body mass known as sarcopenia. Sarcopenia is associated with a lower quality of life and higher healthcare costs. The benefit of strategies that include nutritional intervention, timing of intervention, and physical exercise to improve muscle loss unclear as finding from studies investigating this issue have been inconsistent. We have performed a systematic review and meta-analysis to assess the ability of protein or amino acid supplementation to augment lean body mass or strength of leg muscles in elderly patients.Nine studies met the inclusion criteria of being a prospective comparative study or randomized controlled trial (RCT that compared the efficacy of an amino acid or protein supplement intervention with that of a placebo in elderly people (≥ 65 years for the improvement of lean body mass (LBM, leg muscle strength or reduction associated with sarcopenia.The overall difference in mean change from baseline to the end of study in LBM between the treatment and placebo groups was 0.34 kg which was not significant (P = 0.386. The overall differences in mean change from baseline in double leg press and leg extension were 2.14 kg (P = 0.748 and 2.28 kg (P = 0.265, respectively, between the treatment group and the placebo group.These results indicate that amino acid/protein supplements did not increase lean body mass gain and muscle strength significantly more than placebo in a diverse elderly population.

  9. Amount, Distribution, and Quality of Protein Intake Are Not Associated with Muscle Mass, Strength, and Power in Healthy Older Adults without Functional Limitations—An enable Study

    Directory of Open Access Journals (Sweden)

    Anne Gingrich

    2017-12-01

    Full Text Available To maintain muscle mass in older age, several aspects regarding the amount and distribution of protein intake have been suggested. Our objective was to investigate single and combined associations of daily protein intake, evenness of protein distribution across the three main meals, number of meals providing ≥0.4 g protein/kg body weight (BW, and number of meals providing ≥2.5 g leucine, with muscle mass, strength, and power in successful agers. In this cross-sectional study in 97 healthy community-dwelling adults without functional limitations aged 75–85 years, protein intake was assessed using 7-day food records. Muscle mass, leg muscle strength, leg muscle power, and handgrip strength were measured according to standardized protocols. Mean daily protein intake was 0.97 ± 0.28 g/kg BW and the coefficient of variance between main meals was 0.53 ± 0.19. Per day, 0.72 ± 0.50 meals providing ≥0.4 g protein/kg BW and 1.11 ± 0.76 meals providing ≥2.5 g leucine were consumed. No correlations between single or combined aspects of protein intake and skeletal muscle index, leg muscle power, leg muscle strength, or handgrip strength were observed (Spearman’s r of −0.280 to 0.291. In this sample of healthy older adults without functional limitations, aspects of protein intake were not associated with muscle mass, strength, or power.

  10. Associations of Sarcopenia and Sarcopenic Obesity With Metabolic Syndrome Considering Both Muscle Mass and Muscle Strength

    Science.gov (United States)

    2016-01-01

    Objectives: We investigated the associations of sarcopenia-defined both in terms of muscle mass and muscle strength-and sarcopenic obesity with metabolic syndrome. Methods: Secondary data pertaining to 309 subjects (85 men and 224 women) were collected from participants in exercise programs at a health center in a suburban area. Muscle mass was measured using bioelectrical impedance analysis, and muscle strength was measured via handgrip strength. Sarcopenia based on muscle mass alone was defined as a weight-adjusted skeletal muscle mass index more than two standard deviations below the mean of a sex-specific young reference group (class II sarcopenia). Two cut-off values for low handgrip strength were used: the first criteria were sarcopenia and being in the two highest quintiles of total body fat percentage among the subjects. The associations of sarcopenia and sarcopenic obesity with metabolic syndrome were evaluated using logistic regression models. Results: The age-adjusted risk ratios (RRs) of metabolic syndrome being compared in people with or without sarcopenia defined in terms of muscle mass were 1.25 (95% confidence interval [CI], 1.06 to 1.47, p=0.008) in men and 1.12 (95% CI, 1.06 to 1.19, psarcopenia defined in terms of muscle mass and sarcopenic obesity with metabolic syndrome were statistically significant in both men and women. Therefore, sarcopenia and sarcopenic obesity must be considered as part of the community-based management of non-communicable diseases. PMID:26841883

  11. Novel biomarkers of changes in muscle mass or muscle pathology

    DEFF Research Database (Denmark)

    Arvanitidis, Athanasios

    after radiotherapy, before and during the training period. TNNT1 levels were significantly elevated in the patient group compared to the control group, even before engaging in any form of physical activity. After engaging in physical training, the biomarker levels further increased through time......Muscle protein turnover is a dynamic equilibrium that regulates the body composition and homeostasis through various cytokines and proteases. When the balance between protein synthesis and protein degradation is altered, proper muscle function and regeneration is being hampered, affecting patient...... significantly affect several of the biomarkers levels measured in this study, most prominently CRPM and PINP, indicative of significantly altered turnover of extracellular matrix components and CRPM. C3M correlated with Interferon gene score, in PM and DM, and CRPM with MMT8 score in DM. We further developed...

  12. More gain less pain: balance control learning shifts the activation patterns of leg and neck muscles and increases muscular parsimony.

    Science.gov (United States)

    Iodice, Pierpaolo; Cesinaro, Stefano; Romani, Gian Luca; Pezzulo, Giovanni

    2015-07-01

    Athletes such as skaters or surfers maintain their balance on very unstable platforms. Remarkably, the most skilled athletes seem to execute these feats almost effortlessly. However, the dynamics that lead to the acquisition of a defined and efficient postural strategy are incompletely known. To understand the posture reorganization process due to learning and expertise, we trained twelve participants in a demanding balance/posture maintenance task for 4 months and measured their muscular activity before and after a (predictable) disturbance cued by an auditory signal. The balance training determined significant delays in the latency of participants' muscular activity: from largely anticipatory muscular activity (prior to training) to a mixed anticipatory-compensatory control strategy (after training). After training, the onset of activation was delayed for all muscles, and the sequence of activation systematically reflected the muscle position in the body from top to bottom: neck/upper body muscles were recruited first and in an anticipatory fashion, whereas leg muscles were recruited after the disturbance onset, producing compensatory adjustments. The resulting control strategy includes a mixture of anticipatory and compensatory postural adjustments, with a systematic sequence of muscular activation reflecting the different demands of neck and leg muscles. Our results suggest that subjects learned the precise timing of the disturbance onset and used this information to deploy postural adjustments just-in-time and to transfer at least part of the control of posture from anticipatory to less-demanding feedback-based strategies. In turn, this strategy shift increases the cost-efficiency of muscular activity, which is a key signature of skilled performance.

  13. Muscle Protein Turnover and the Molecular Regulation of Muscle Mass during Hypoxia.

    Science.gov (United States)

    Pasiakos, Stefan M; Berryman, Claire E; Carrigan, Christopher T; Young, Andrew J; Carbone, John W

    2017-07-01

    : Effects of environmental hypoxia on fat-free mass are well studied. Negative energy balance, increased nitrogen excretion, and fat-free mass loss are commonly observed in lowlanders sojourning at high altitude. Reductions in fat-free mass can be minimized if energy consumption matches energy expenditure. However, in nonresearch settings, achieving energy balance during high-altitude sojourns is unlikely, and myofibrillar protein mass is usually lost, but the mechanisms accounting for the loss of muscle mass are not clear. At sea level, negative energy balance reduces basal and blunts postprandial muscle protein synthesis, with no relevant change in muscle protein breakdown. Downregulations in muscle protein synthesis and loss of fat-free mass during energy deficit at sea level are largely overcome by consuming at least twice the recommended dietary allowance for protein. Hypoxia may increase or not affect resting muscle protein synthesis, blunt postexercise muscle protein synthesis, and markedly increase proteolysis independent of energy status. Hypoxia-induced mTORC1 dysregulation and an upregulation in calpain- and ubiquitin proteasome-mediated proteolysis may drive catabolism in lowlanders sojourning at high altitude. However, the combined effects of energy deficit, exercise, and dietary protein manipulations on the regulation of muscle protein turnover have never been studied at high altitude. This article reviews the available literature related to the effects of high altitude on fat-free mass, highlighting contemporary studies that assessed the influence of altitude exposure (or hypoxia) on muscle protein turnover and intramuscular regulation of muscle mass. Knowledge gaps are addressed, and studies to identify effective and feasible countermeasures to hypoxia-induced muscle loss are discussed.

  14. Diet, inflammation and skeletal muscle mass in women

    OpenAIRE

    Kelaiditi, Eirini

    2013-01-01

    Evidence is growing that diet, lifestyle factors and chronic inflammation influence sarcopenia. Sarcopenia is the progressive decline of muscle mass, strength and function that occurs with healthy ageing. The ageing process is also associated with a gradual increasing production of pro-inflammatory cytokines, which may potentially enhance the development of sarcopenia. Dietary longitudinal studies have shown associations between protein intake and muscle mass in older people but results of su...

  15. Localization of nerve entry points as targets to block spasticity of the deep posterior compartment muscles of the leg.

    Science.gov (United States)

    Hu, Shuaiyu; Zhuo, Lifan; Zhang, Xiaoming; Yang, Shengbo

    2017-10-01

    To identify the optimal body surface puncture locations and the depths of nerve entry points (NEPs) in the deep posterior compartment muscles of the leg, 60 lower limbs of thirty adult cadavers were dissected in prone position. A curved line on the skin surface joining the lateral to the medial epicondyles of the femur was taken as a horizontal reference line (H). Another curved line joining the lateral epicondyle of the femur to the lateral malleolus was designated the longitudinal reference line (L). Following dissection, the NEPs were labeled with barium sulfate and then subjected to spiral computed tomography scanning. The projection point of the NEP on the posterior skin surface of the leg was designated P, and the projection in the opposite direction across the transverse plane was designated P'. The intersections of P on H and L were identified as P H and P L , and their positions and the depth of the NEP on PP' were measured using the Syngo system and expressed as percentages of H, L, and PP'. The P H points of the tibial posterior, flexor hallucis longus and flexor digitorum longus muscles were located at 38.10, 46.20, and 55.21% of H, respectively. The P L points were located at 25.35, 41.30, and 45.39% of L, respectively. The depths of the NEPs were 49.11, 54.64, and 55.95% of PP', respectively. The accurate location of these NEPs should improve the efficacy and efficiency of chemical neurolysis for treating spasticity of the deep posterior compartment muscles of the leg. Clin. Anat. 30:855-860, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  16. Muscle timing in injured and non-injured leg of athletes with chronic ankle instability in response to a visual stimulus during forward jumping.

    Science.gov (United States)

    Fereydounnia, Sara; Shadmehr, Azadeh; Talebian Moghadam, Saeed; Olyaei, Gholamreza; Jalaie, Shohreh; Tahmasebi, Ali

    2016-01-01

    The aim of this study was to investigate premotor time, motor time and reaction time of the injured and non-injured leg muscles of athletes with chronic ankle instability in response to a visual stimulus during forward jumping. Surface electromyography was performed on injured and non-injured leg of eight athletes with chronic ankle instability during forward jumping. Results showed that premotor time of the peroneus longus was significantly longer in non-injured leg compared with injured leg (489.37 ± 220.22 ms vs. 306.46 ± 142.92 ms, P = 0.031); on the contrary, motor time of the peroneus longus was significantly shorter in non-injured leg compared with injured leg (569.04 ± 318.62 ms vs. 715.12 ± 328.72 ms, P = 0.022). No significant difference was noted in the timing of other calf muscles (P > 0.05). According to the results of this study, rehabilitation protocols, regarding ankle instability, need to put greater emphasis on tasks that require proper timing of muscles and muscle re-education so that protocols could reduce residual symptoms after sprain and prevent recurrent sprains. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Regulation of skeletal muscle oxidative capacity and muscle mass by SIRT3.

    Directory of Open Access Journals (Sweden)

    Ligen Lin

    Full Text Available We have previously reported that the expression of mitochondrial deacetylase SIRT3 is high in the slow oxidative muscle and that the expression of muscle SIRT3 level is increased by dietary restriction or exercise training. To explore the function of SIRT3 in skeletal muscle, we report here the establishment of a transgenic mouse model with muscle-specific expression of the murine SIRT3 short isoform (SIRT3M3. Calorimetry study revealed that the transgenic mice had increased energy expenditure and lower respiratory exchange rate (RER, indicating a shift towards lipid oxidation for fuel usage, compared to control mice. The transgenic mice exhibited better exercise performance on treadmills, running 45% further than control animals. Moreover, the transgenic mice displayed higher proportion of slow oxidative muscle fibers, with increased muscle AMPK activation and PPARδ expression, both of which are known regulators promoting type I muscle fiber specification. Surprisingly, transgenic expression of SIRT3M3 reduced muscle mass up to 30%, likely through an up-regulation of FOXO1 transcription factor and its downstream atrophy gene MuRF-1. In summary, these results suggest that SIRT3 regulates the formation of oxidative muscle fiber, improves muscle metabolic function, and reduces muscle mass, changes that mimic the effects of caloric restriction.

  18. Relationship between different protein intake recommendations with muscle mass and muscle strength.

    Science.gov (United States)

    Lemieux, F C; Filion, M-E; Barbat-Artigas, S; Karelis, A D; Aubertin-Leheudre, M

    2014-06-01

    The purpose of the present study was to examine the relationship between two different levels of protein intake (0.8 vs.1.2 g/kg body weight/day) with muscle mass and muscle strength. Seventy-two postmenopausal women were recruited. Body composition (bioelectrical impedance analysis), muscle strength (dynamometer), energy metabolism (indirect calorimetry) and dietary intake (dietary journal) were measured. We divided the women into two groups. Women with a protein intake of ≥ 1.2 g/kg body weight/day were placed in the Protein ≥ 1.2 group (n = 35), whereas women with a protein intake of 0.8-1.19 g/kg body weight/day were categorized in the Protein 0.8-1.19 group (n = 32). No significant difference was observed between groups for age, height, skeletal muscle mass, resting energy expenditure, total energy expenditure, carbohydrate and lipid intake. Significant differences between groups were observed for body mass index (p mass (p muscle strength (hand grip and knee extensors) (p Protein ≥ 1.2 group presented a higher muscle strength as well as a lower body mass index and fat mass compared to the Protein 0.8-1.19 group. In addition, the group with a protein intake of ≥ 1.2 g/kg body weight/day presented significantly higher energy intake (p = 0.002), and essential (p muscle strength was adjusted for essential or non-essential amino acids, differences in muscle strength persisted. The present study indicates higher levels of muscle strength in postmenopausal women with a protein intake of ≥ 1.2 g/kg body weight/day compared to 0.8-1.19 g/kg body weight/day despite no differences in muscle mass.

  19. Local temperature-sensitive mechanisms are important mediators of limb tissue hyperemia in the heat-stressed human at rest and during small muscle mass exercise.

    Science.gov (United States)

    Chiesa, Scott T; Trangmar, Steven J; Kalsi, Kameljit K; Rakobowchuk, Mark; Banker, Devendar S; Lotlikar, Makrand D; Ali, Leena; González-Alonso, José

    2015-07-15

    Limb tissue and systemic blood flow increases with heat stress, but the underlying mechanisms remain poorly understood. Here, we tested the hypothesis that heat stress-induced increases in limb tissue perfusion are primarily mediated by local temperature-sensitive mechanisms. Leg and systemic temperatures and hemodynamics were measured at rest and during incremental single-legged knee extensor exercise in 15 males exposed to 1 h of either systemic passive heat-stress with simultaneous cooling of a single leg (n = 8) or isolated leg heating or cooling (n = 7). Systemic heat stress increased core, skin and heated leg blood temperatures (Tb), cardiac output, and heated leg blood flow (LBF; 0.6 ± 0.1 l/min; P 0.05). Increased heated leg deep tissue blood flow was closely related to Tb (R(2) = 0.50; P 0.05), despite unchanged systemic temperatures and hemodynamics. During incremental exercise, heated LBF was consistently maintained ∼ 0.6 l/min higher than that in the cooled leg (P conductance in both legs showing a strong correlation with their respective local Tb (R(2) = 0.85 and 0.95, P < 0.05). We conclude that local temperature-sensitive mechanisms are important mediators in limb tissue perfusion regulation both at rest and during small-muscle mass exercise in hyperthermic humans. Copyright © 2015 the American Physiological Society.

  20. Hop performance and leg muscle power in athletes: Reliability of a test battery.

    Science.gov (United States)

    Kockum, Britta; Heijne, Annette I-L M

    2015-08-01

    To measure the absolute and relative reliability and the smallest real difference (SRD) in three commonly used hop tests, two leg-power tests and the single-leg squat jump. Methodological study. Clinical setting. Fourteen healthy athletes (seven women and seven men) were evaluated in a standardized test-retest design. The Intra-class correlation coefficient (ICC2.1), Standard Error of Measurement (SEM) and SRD were calculated for the vertical jump, one-leg hop for distance, side-hop, single-leg squat jump and knee-flexion and knee-extension power tests. All tests showed good to excellent ICC (0.84-0.98). The SEM (%) ranged between 3.4 and 11.1 for the four hop tests and between 8.1 and 12.4 for the leg-power tests. The SRD (%) for the hop tests ranged between 9.3 and 30.7 and for the three power tests between 22.4 and 34.3. The absolute reliability of this test protocol showed good to excellent ICC values and measurement errors of approximately 10%. This instrument can be recommended for determining function in terms of power in healthy athletes or late in the rehabilitation process. The tests' methodological errors must be considered and caution should be taken regarding the standardization procedure during testing. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. The effects of anthropometry and leg muscle power on drive and transition phase of acceleration: a longitudinal study on young soccer players.

    Science.gov (United States)

    Nikolaidis, Pantelis T; Ingebrigtsen, Jorgen; Jeffreys, Ian

    2016-10-01

    The aim of this study was to examine the effect of anthropometry and leg muscle power on accelerative ability and its phases (drive and transition). Thirty-six soccer players (age 12.4±1.2 years, body mass 49.9±8.9 kg and height 154.2±10.3 cm) were tested twice, in the beginning and in the end of competitive season, for anthropometric characteristics, countermovement jump and 20-meter acceleration (split 0-10 meters and 10-20 meters, indices of drive and transition, respectively). The soccer players were grouped according to seasonal changes in 20-meter acceleration (Δacc) in responders (Δacc≤-0.10 s), control (-0.05≤Δacc≤0.08 s) and non-responders (Δacc≥0.10 s). Compared with the non-responders at baseline, the responders were younger (-2.0 years [-2.8;-1.1]), shorter (-10.1 cm [-19.4;-0.7]), with higher body fat percentage (7.7% [2.7%;12.6%]) and fat mass (4.1 kg [0.7;7.4]), and lower performance in the countermovement jump (-8.9 cm [-13.9;-4.0]) and 20 m acceleration (0.63 s [0.39;0.87]); during the season they had smaller body mass gain (-2.8 kg [-5.4;-0.1]), decreased Body Mass Index (BMI, -1.0 kg/m2 [-1.9;0]) and greater improvement in the 20-meter acceleration (-0.33 s [-0.38;-0.28]). The effect size for these between-group differences was large (η2≥0.18). The Δacc and Δ10-20 were moderately correlated with body mass difference (r=0.48 and r=0.53, P<0.01, respectively) and ΔBMI (r=0.50 and r=0.51, P<0.01, respectively), whereas the Δ0-10 was correlated with ΔBMI (r=0.34, P<0.05) and ΔCMJ (r=-0.34, P<0.05). The findings indicated that the changes in body mass had the largest effect on changes in accelerative ability and on both two phases (drive and transition). On the contrary, changes in leg muscle power had impact only on the drive phase of the acceleration.

  2. Relation between body mass index percentile and muscle strength ...

    African Journals Online (AJOL)

    Relation between body mass index percentile and muscle strength and endurance. ... Egyptian Journal of Medical Human Genetics ... They were divided into three groups according to their body mass index percentile where group (a) is equal to or more than 5% percentile yet less than 85% percentile, group (b) is equal to ...

  3. The Influence of Dual Pressure Biofeedback Units on Pelvic Rotation and Abdominal Muscle Activity during the Active Straight Leg Raise in Women with Chronic Lower Back Pain

    OpenAIRE

    Noh, Kyung-Hee; Kim, Ji-Won; Kim, Gyoung-Mo; Ha, Sung-Min; Oh, Jae-Seop

    2014-01-01

    [Purpose] This study was performed to assess the influence of applying dual pressure biofeedback units (DPBUs) on the angle of pelvic rotation and abdominal muscle activity during the active straight leg raise (ASLR). [Subjects] Seventeen patients with low-back pain (LBP) participated in this study. [Methods] The subjects were asked to perform an active straight leg raise (ASLR) without a PBU, with a single PBU, and with DPBUs. The angles of pelvic rotation were measured using a three-dimensi...

  4. Interdependence of torque, joint angle, angular velocity and muscle action during human multi-joint leg extension.

    Science.gov (United States)

    Hahn, Daniel; Herzog, Walter; Schwirtz, Ansgar

    2014-08-01

    Force and torque production of human muscles depends upon their lengths and contraction velocity. However, these factors are widely assumed to be independent of each other and the few studies that dealt with interactions of torque, angle and angular velocity are based on isolated single-joint movements. Thus, the purpose of this study was to determine force/torque-angle and force/torque-angular velocity properties for multi-joint leg extensions. Human leg extension was investigated (n = 18) on a motor-driven leg press dynamometer while measuring external reaction forces at the feet. Extensor torque in the knee joint was calculated using inverse dynamics. Isometric contractions were performed at eight joint angle configurations of the lower limb corresponding to increments of 10° at the knee from 30 to 100° of knee flexion. Concentric and eccentric contractions were performed over the same range of motion at mean angular velocities of the knee from 30 to 240° s(-1). For contractions of increasing velocity, optimum knee angle shifted from 52 ± 7 to 64 ± 4° knee flexion. Furthermore, the curvature of the concentric force/torque-angular velocity relations varied with joint angles and maximum angular velocities increased from 866 ± 79 to 1,238 ± 132° s(-1) for 90-50° knee flexion. Normalised eccentric forces/torques ranged from 0.85 ± 0.12 to 1.32 ± 0.16 of their isometric reference, only showing significant increases above isometric and an effect of angular velocity for joint angles greater than optimum knee angle. The findings reveal that force/torque production during multi-joint leg extension depends on the combined effects of angle and angular velocity. This finding should be accounted for in modelling and optimisation of human movement.

  5. Straight-leg rasing in 'short hamstrings'. An experimental study of muscle elasticy and defense reactions.

    NARCIS (Netherlands)

    Göeken, Ludwig Nanno Hiltjo

    1988-01-01

    The central guestion asked in this thesis is whether an Experimental Straight-Leg Raising test (E.S.L.R.) can contribute to the solution of a diagnostical problem frequently encountered in rehabilitation medicine. It concerns the determination of the cause of the movement restriction in patients who

  6. Homologous muscle contraction during unilateral movement does not show a dominant effect on leg representation of the ipsilateral primary motor cortex.

    Directory of Open Access Journals (Sweden)

    Shin-Yi Chiou

    Full Text Available Co-activation of homo- and heterotopic representations in the primary motor cortex (M1 ipsilateral to a unilateral motor task has been observed in neuroimaging studies. Further analysis showed that the ipsilateral M1 is involved in motor execution along with the contralateral M1 in humans. Additionally, transcranial magnetic stimulation (TMS studies have revealed that the size of the co-activation in the ipsilateral M1 has a muscle-dominant effect in the upper limbs, with a prominent decline of inhibition within the ipsilateral M1 occurring when a homologous muscle contracts. However, the homologous muscle-dominant effect in the ipsilateral M1 is less clear in the lower limbs. The present study investigates the response of corticospinal output and intracortical inhibition in the leg representation of the ipsilateral M1 during a unilateral motor task, with homo- or heterogeneous muscles. We assessed functional changes within the ipsilateral M1 and in corticospinal outputs associated with different contracting muscles in 15 right-handed healthy subjects. Motor tasks were performed with the right-side limb, including movements of the upper and lower limbs. TMS paradigms were measured, consisting of short-interval intracortical inhibition (SICI and recruitment curves (RCs of motor evoked potentials (MEPs in the right M1, and responses were recorded from the left rectus femoris (RF and left tibialis anterior (TA muscles. TMS results showed that significant declines in SICI and prominent increases in MEPs of the left TA and left RF during unilateral movements. Cortical activations were associated with the muscles contracting during the movements. The present data demonstrate that activation of the ipsilateral M1 on leg representation could be increased during unilateral movement. However, no homologous muscle-dominant effect was evident in the leg muscles. The results may reflect that functional coupling of bilateral leg muscles is a reciprocal

  7. Effects of progressive strength training on muscle mass in type 2 diabetes mellitus patients determined by computed tomography

    International Nuclear Information System (INIS)

    Cauza, E.; Strehblow, C.; Hanusch-Enserer, U.; Fasching, P.; Metz-Schimmerl, S.; Strasser, B.; Kostner, K.; Dunstan, D.; Haber, P.

    2009-01-01

    To examine the effect of a 4-month progressive strength training program on muscle and fat mass assessed by computed tomography (CT) in type 2 diabetes mellitus (T2DM) patients, and to assess the relationships of changes in muscle cross-section area (CSA) with glycaemic control. Twenty adults (mean age ± SE: 56.4 ± 0.9 a) with T2DM participated in a supervised strength training program for 4 months 3 days/week. Muscle and fat areas of the quadriceps muscle were estimated by CT volumetry before and immediately after the training. Glycaemic (HbA1c) and anthropometric (BMI, skinfolds) measurements were assessed at 0 and 4 months, respectively. After strength training, muscle strength increased significantly in all measured muscle groups. Quadriceps size (CSA of the muscle) was increased by 2.4 % (from 7.99 ± 0.3 cm 3 to 8.18 ± 0.3 cm 3 , p = 0.003) for the right extremity, 3.9 % (from 8.1 ± 0.4 cm 3 to 8.41 ± 0.5 cm 3 , p = 0.04) for the left side. Fat tissue CSA reduced from 0.66 ± 0.1 cm 3 to 0.56 ± 0.12 cm 3 for the right leg (15.3 % reduction) and from 0.58 ± 0.12 cm 3 to 0.37 ± 0.13 cm 3 for the left leg (35.8 % reduction), resulting in a mean fat CSA reduction of 24.8 %. Fat mass assessed by skin folds was significantly reduced and lean body mass was significantly increased. The change in muscle CSA was not correlated with the changes in HbA1c or muscle strength. Strength training significantly improves both muscle mass and the muscle to fat ratio in T2DM. However, changes in muscle observed with computed tomography were not related to changes observed in HbA1c with training. (author) [de

  8. [Variation of muscle mass and weight in critical patient].

    Science.gov (United States)

    Valls-Matarín, J; del Cotillo-Fuente, M; Grané-Mascarell, N; Quintana, S

    2015-01-01

    Quantify the muscle mass and body weight variation in critically ill patients and to identify associated factors. A descriptive follow-up study. Data for demographic variables, body weight, fluid balance, daily kilocalories, the amount of sedation and muscle relaxants received and motor physiotherapy applied were collected. Three consecutive measurements were performed in the brachial biceps and quadriceps rectus by using ultrasound, upon admission and every 5 days until discharge. 68 patients were included. Average age was of 73.5 [57-78,5] years. The median length of stay was 9.5 [5.5 -15] days. The median 16 (SD=5.7) daily kilocalories per kg/weight, 91.2% received sedation, 44.1% received muscle relaxants and 20% received physiotherapy. The patients presented a muscle wasting of 4.9 (SD=3.9)mm, p <.001 in the brachial biceps and 5.6 (SD=4.8)mm, p <.001 in the quadriceps rectus. Regression analysis selected the length of stay and the muscle relaxants are the most influential variables in the brachial biceps muscle wasting (R2=0.4), and length of stay as the most influential in the quadriceps rectus muscle wasting (R2=0.3). Patient's mean body weight on admission was of 81.1 (SD=15)kg and 81.2 (SD=14.2)kg on discharge, p=.95. The critically ill patient presents a significant muscle waste related with the length of stay and the treatment received with muscle relaxants. Patients are being discharged with a similar body weight to which they were admitted but with a significant reduction of muscle mass. Copyright © 2014 Elsevier España, S.L.U. y SEEIUC. All rights reserved.

  9. Muscle fatigue and exhaustion during dynamic leg exercise in normoxia and hypobaric hypoxia

    DEFF Research Database (Denmark)

    Fulco, C S; Lewis, S F; Frykman, Peter

    1996-01-01

    Using an exercise device that integrates maximal voluntary static contraction (MVC) of knee extensor muscles with dynamic knee extension, we compared progressive muscle fatigue, i.e., rate of decline in force-generating capacity, in normoxia (758 Torr) and hypobaric hypoxia (464 Torr). Eight...

  10. Fatigue and recovery from dynamic contractions in men and women differ for arm and leg muscles.

    Science.gov (United States)

    Senefeld, Jonathon; Yoon, Tejin; Bement, Marie Hoeger; Hunter, Sandra K

    2013-09-01

    Whether there is a gender difference in fatigue and recovery from maximal velocity fatiguing contractions and across muscles is not understood. Sixteen men and 19 women performed 90 isotonic contractions at maximal voluntary shortening velocity (maximal velocity concentric contractions, MVCC) with the elbow flexor and knee extensor muscles (separate days) at a load equivalent to 20% maximal voluntary isometric contraction (MVIC). Power (from MVCCs) decreased similarly for men and women for both muscles (P > 0.05). Men and women had similar declines in MVIC of elbow flexors, but men had greater reductions in knee extensor MVIC force and MVIC electromyogram activity than women (P muscle fatigue often observed during isometric tasks was diminished during fast dynamic contractions for upper and lower limb muscles. Copyright © Published 2013 by Wiley Periodicals, Inc. This article is a US Government wmusork and, as such, is in the public domain in the United States of America.

  11. Pneumatic muscle actuator for resistive exercise in microgravity: test with a leg model.

    Science.gov (United States)

    Serres, Jennifer L; Phillips, Chandler A; Reynolds, David B; Mohler, Stanley R; Rogers, Dana B; Repperger, Daniel W; Gerschutz, Maria J

    2010-02-01

    A proof-of-concept demonstration is described in which a DC servomotor (simulating the quadriceps of a human operator) rotated a pulley 90 degrees (simulating knee extension). A pneumatic muscle actuator (PMA) generated an opposing force (antagonist) to the rotating pulley. One application of such a device is for use in microgravity environments because the PMA is compact, simple, and of relatively small mass (283 g). In addition, the operator can set a computer-controlled force-level range in response to individual user changes in exercise conditioning over time. A PMA was used in this study and interacted with a DC servomotor. For each trial, the PMA contracted in response to internal pressure. An input voltage profile activated the DC servomotor, resulting in the following three phases: an isokinetic counterclockwise pulley rotation of 90 degrees over 5 s (Phase I), the position was held for 5 s (Phase II), and an isokinetic clockwise rotation of 90 degrees over 5 s (Phase III). Root mean square error (RMSE) values were used to evaluate the pulley rotation. For Phase I, when the PMA pressures (in kPa) were 300, 450, and 575, the percent RMSE, respectively, were 5.24, 6.23, and 4.59. For Phase II, the percent RMSE were 2.81, 2.57, and 5.63, respectively. For Phase III, the percent RMSE were 5.69, 2.63, and 3.30, respectively. This study presents a demonstration of a PMA device that can enhance exercise by providing a wide range of resistive loads.

  12. Monitoring of color and pH in muscles of pork leg (m. adductor and m. semimembranosus

    Directory of Open Access Journals (Sweden)

    Martina Bednářová

    2014-02-01

    Full Text Available In order to identify PSE pork meat, pH and color testing was performed directly in a cutting plant (72 hours post mortem in this research. Specifically pork leg muscles musculi adductor (AD and semimembranosus (SM from five selected suppliers (A, B, C, D, E were examined. Twenty samples of meat for each muscle were examined from each supplier. The measured pH values ranged from 5.43 to 5.63, and the L* values from 46.13 to 57.18. No statistically significant differences in pH values and color were detected among the various suppliers with the exception of the a* and b* parameters for two suppliers, namely A and B (p<0.01. On the contrary, a statistically significant difference (p<0.5 was recorded between individual muscles (AD/SM across all the suppliers (A, B, C, D, E with the exception of a* parameter from suppliers B, C, D, E, and pH values for the E supplier. Our results revealed that individual muscles differ in values of pH and color. In comparison with literature, pH and lightness L* values in musculus adductor point to PSE (pale, soft and exudative meat, while the values of musculus semimebranosus to RFN (red, firm and non-exudative. Use of PSE meat in production of meat products can cause several problems. In particular, it causes light color, low water-holding capacity, poor fat emulsifying ability, lower yield, granular or crumbly texture and poor consistency of the finished product. Therefore classification of the meat directly cutting plant may be possible solution for this problem. The finished product pruduces from muscles of musculi semimembranosus can obtain better quality than the finished product from musculi adductor.

  13. The effects of kinesthetic illusory sensation induced by a visual stimulus on the corticomotor excitability of the leg muscles.

    Science.gov (United States)

    Aoyama, T; Kaneko, F; Hayami, T; Shibata, E

    2012-04-11

    A novel method of visual stimulus, reported by Kaneko et al. [14], induced a vivid kinesthetic illusion and increased the corticomotor excitability of the finger muscles without any overt movement. To explore the effect of this method on the lower limbs, motor evoked potentials (MEP) were recorded from the left tibialis anterior (TA) and soleus muscles using transcranial magnetic stimulation (TMS). A computer screen that showed the moving image of an ankle movement was placed over the subject's leg, and its position was modulated to induce an illusory sensation that the subject's own ankle was moving (illusion condition). TMS was delivered at rest and at two different times during the illusion condition (ankle dorsiflexion phase: illusion-DF; ankle plantarflexion phase: illusion-PF). The MEP amplitude of the TA, which is the agonist muscle for ankle dorsiflexion, was significantly increased during the illusion-DF condition. This indicated that the visual stimulus showing the moving image of an ankle movement could induce a kinesthetic illusion and selectively increase the corticomotor excitability in an agonist muscle for an illusion, as was previously reported for an upper limb. The MEP amplitude of the soleus, which is the agonist muscle for ankle plantarflexion, increased during the illusion-PF condition, but not significantly. Because of the vividness of the illusory sensation was significantly greater during the illusion-DF condition than the illusion-PF condition, we concluded that the vividness of the illusory sensation had a crucial role in increasing corticomotor excitability. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  14. Community-dwelling female fallers have lower muscle density in their lower legs than non-fallers: evidence from the Saskatoon Canadian Multicentre Osteoporosis Study (CaMos) cohort.

    Science.gov (United States)

    Frank, A W; Farthing, J P; Chilibeck, P D; Arnold, C M; Olszynski, W P; Kontulainen, S A

    2015-01-01

    Our objectives were to determine whether peripheral quantitative computed tomography (pQCT)-derived lower leg muscle density and area, and basic functional mobility differ between community-dwelling older women who do and do not report recent falls. Matched case-control comparison. Academic biomedical imaging laboratory. 147 Women, 60 years or older (mean age 74.3 y, SD 7.7) recruited from a longitudinal, population-based cohort representing community-dwelling residents in the area of Saskatoon, Canada. A cross-sectional pQCT scan of the non-dominant lower leg was acquired to determine muscle density and area. Basic functional mobility (Timed Up and Go Test [TUG]) and SF36 health status were also measured. Fallers (one or more falls) and non-fallers (no falls) were grouped according to a 12-month retrospective survey and matched on measured covariates. The muscle density of fallers (n = 35) was a median of 2.1 mg/cm3 lower (P = 0.019, 95% C.I. -3.9 to -0.1) than non-fallers (n = 78) after matching and adjusting for age, body mass index, and SF36 general health scores. Muscle area and TUG did not differ between fallers and non-fallers. Muscle density may serve as a physiological marker in the assessment of lower leg muscular health and fall risk in community-dwelling elderly women. These results are limited to our study population who were mostly Caucasian. Prospective studies are required for verification.

  15. Supplementing Breakfast with a Vitamin D and Leucine-Enriched Whey Protein Medical Nutrition Drink Enhances Postprandial Muscle Protein Synthesis and Muscle Mass in Healthy Older Men.

    Science.gov (United States)

    Chanet, Audrey; Verlaan, Sjors; Salles, Jérôme; Giraudet, Christophe; Patrac, Véronique; Pidou, Véronique; Pouyet, Corinne; Hafnaoui, Nordine; Blot, Adeline; Cano, Noël; Farigon, Nicolas; Bongers, Anke; Jourdan, Marion; Luiking, Yvette; Walrand, Stéphane; Boirie, Yves

    2017-12-01

    Background: A promising strategy to help older adults preserve or build muscle mass is to optimize muscle anabolism through providing an adequate amount of high-quality protein at each meal. Objective: This "proof of principle" study investigated the acute effect of supplementing breakfast with a vitamin D and leucine-enriched whey protein medical nutrition drink on postprandial muscle protein synthesis and longer-term effect on muscle mass in healthy older adults. Methods: A randomized, placebo-controlled, double-blind study was conducted in 24 healthy older men [mean ± SD: age 71 ± 4 y; body mass index (in kg/m 2 ) 24.7 ± 2.8] between September 2012 and October 2013 at the Unit of Human Nutrition, University of Auvergne, Clermont-Ferrand, France. Participants received a medical nutrition drink [test group; 21 g leucine-enriched whey protein, 9 g carbohydrates, 3 g fat, 800 IU cholecalciferol (vitamin D 3 ), and 628 kJ] or a noncaloric placebo (control group) before breakfast for 6 wk. Mixed muscle protein fractional synthesis rate (FSR) was measured at week 0 in the basal and postprandial state, after study product intake with a standardized breakfast with the use of l-[ 2 H 5 ]-phenylalanine tracer methodology. The longer-term effect of the medical nutrition drink was evaluated by measurement of appendicular lean mass, representing skeletal muscle mass at weeks 0 and 6, by dual-energy X-ray absorptiometry. Results: Postprandial FSR (0-240 min) was higher in the test group than in the control group [estimate of difference (ED): 0.022%/h; 95% CI: 0.010%/h, 0.035%/h; ANCOVA, P = 0.001]. The test group gained more appendicular lean mass than the control group after 6 wk (ED: 0.37 kg; 95% CI: 0.03, 0.72 kg; ANCOVA, P = 0.035), predominantly as leg lean mass (ED: 0.30 kg; 95% CI: 0.03, 0.57 kg; ANCOVA, P = 0.034). Conclusions: Supplementing breakfast with a vitamin D and leucine-enriched whey protein medical nutrition drink stimulated postprandial muscle protein

  16. Divergent muscle sympathetic responses to dynamic leg exercise in heart failure and age-matched healthy subjects.

    Science.gov (United States)

    Notarius, Catherine F; Millar, Philip J; Murai, Hisayoshi; Morris, Beverley L; Marzolini, Susan; Oh, Paul; Floras, John S

    2015-02-01

    People with diminished ventricular contraction who develop heart failure have higher sympathetic nerve firing rates at rest compared with healthy individuals of a similar age and this is associated with less exercise capacity. During handgrip exercise, sympathetic nerve activity to muscle is higher in patients with heart failure but the response to leg exercise is unknown because its recording requires stillness. We measured sympathetic activity from one leg while the other leg cycled at a moderate level and observed a decrease in nerve firing rate in healthy subjects but an increase in subjects with heart failure. Because these nerves release noradrenaline, which can restrict muscle blood flow, this observation helps explain the limited exercise capacity of patients with heart failure. Lower nerve traffic during exercise was associated with greater peak oxygen uptake, suggesting that if exercise training attenuated sympathetic outflow functional capacity in heart failure would improve. The reflex fibular muscle sympathetic nerve (MSNA) response to dynamic handgrip exercise is elicited at a lower threshold in heart failure with reduced ejection fraction (HFrEF). The present aim was to test the hypothesis that the contralateral MSNA response to mild to moderate dynamic one-legged exercise is augmented in HFrEF relative to age- and sex-matched controls. Heart rate (HR), blood pressure and MSNA were recorded in 16 patients with HFrEF (left ventricular ejection fraction = 31 ± 2%; age 62 ± 3 years, mean ± SE) and 13 healthy control subjects (56 ± 2 years) before and during 2 min of upright one-legged unloaded cycling followed by 2 min at 50% of peak oxygen uptake (V̇O2,peak). Resting HR and blood pressure were similar between groups whereas MSNA burst frequency was higher (50.0 ± 2.0 vs. 42.3 ± 2.7 bursts min(-1), P = 0.03) and V̇O2,peak lower (18.0 ± 2.0 vs. 32.6 ± 2.8 ml kg(-1) min(-1), P Exercise increased HR (P exercise in the healthy controls but

  17. Age Differences in Dynamic Fatigability and Variability of Arm and Leg Muscles: Associations with Physical Function

    Science.gov (United States)

    Senefeld, Jonathon; Yoon, Tejin; Hunter, Sandra K.

    2016-01-01

    Introduction It is not known whether the age-related increase in fatigability of fast dynamic contractions in lower limb muscles also occurs in upper limb muscles. We compared age-related fatigability and variability of maximal-effort repeated dynamic contractions in the knee extensor and elbow flexor muscles; and determined associations between fatigability, variability of velocity between contractions and functional performance. Methods 35 young (16 males; 21.0±2.6 years) and 32 old (18 males; 71.3±6.2 years) adults performed a dynamic fatiguing task involving 90 maximal-effort, fast, concentric, isotonic contractions (1 contraction/3 s) with a load equivalent to 20% maximal voluntary isometric contraction (MVIC) torque with the elbow flexor and knee extensor muscles on separate days. Old adults also performed tests of balance and walking endurance. Results Old adults had greater fatigue-related reductions in peak velocity compared with young adults for both the elbow flexor and knee extensor muscles (P0.05). Old adults had greater variability of peak velocity during the knee extensor, but not during the elbow flexor fatiguing task. The age difference in fatigability was greater for the knee extensor muscles (35.9%) compared with elbow flexor muscles (9.7%, Pmuscles was associated with greater walking endurance (r=−0.34, P=0.048) and balance (r=−0.41, P=0.014) among old adults. Conclusions An age-related increase in fatigability of a dynamic fatiguing task was greater for the knee extensor compared with the elbow flexor muscles in males and females, and greater fatigability was associated with lesser walking endurance and balance. PMID:27989926

  18. Myoglobin plasma level related to muscle mass and fiber composition: a clinical marker of muscle wasting?

    Science.gov (United States)

    Weber, Marc-André; Kinscherf, Ralf; Krakowski-Roosen, Holger; Aulmann, Michael; Renk, Hanna; Künkele, Annette; Edler, Lutz; Kauczor, Hans-Ulrich; Hildebrandt, Wulf

    2007-08-01

    Progressive muscle wasting is a central feature of cancer-related cachexia and has been recognized as a determinant of poor prognosis and quality of life. However, until now, no easily assessable clinical marker exists that allows to predict or to track muscle wasting. The present study evaluated the potential of myoglobin (MG) plasma levels to indicate wasting of large locomotor muscles and, moreover, to reflect the loss of MG-rich fiber types, which are most relevant for daily performance. In 17 cancer-cachectic patients (weight loss 22%) and 27 age- and gender-matched healthy controls, we determined plasma levels of MG and creatine kinase (CK), maximal quadriceps muscle cross-sectional area (CSA) by magnetic resonance imaging, muscle morphology and fiber composition in biopsies from the vastus lateralis muscle, body cell mass (BCM) by impedance technique as well as maximal oxygen uptake (VO(2)max). In cachectic patients, plasma MG, muscle CSA, BCM, and VO(2)max were 30-35% below control levels. MG showed a significant positive correlation to total muscle CSA (r = 0.65, p max as an important functional readout. CK plasma levels appear to be less reliable because prolonged increases are observed in even subclinical myopathies or after exercise. Notably, cancer-related muscle wasting was not associated with increases in plasma MG or CK in this study.

  19. Leg extensor muscle strength, postural stability, and fear of falling after a 2-month home exercise program in women with severe knee joint osteoarthritis.

    Science.gov (United States)

    Rätsepsoo, Monika; Gapeyeva, Helena; Sokk, Jelena; Ereline, Jaan; Haviko, Tiit; Pääsuke, Mati

    2013-01-01

    BACKGROUND AND OBJECTIVE. The aim of this study was to compare the leg extensor muscle strength, the postural stability, and the fear of falling in the women with severe knee joint osteoarthritis (OA) before and after a 2-month home exercise program (HEP). MATERIAL AND METHODS. In total, 17 women aged 46-72 years with late-stage knee joint OA scheduled for total knee arthroplasty participated in this study before and after the 2-month HEP with strengthening, stretching, balance, and step exercises. The isometric peak torque (PT) of the leg extensors and postural stability characteristics when standing on a firm or a foam surface for 30 seconds were recorded. The fear of falling and the pain intensity (VAS) were estimated. RESULTS. A significant increase in the PT and the PT-to-body weight (PT-to-BW) ratio of the involved leg as well as the bilateral PT and the PT-to-BW ratio was found after the 2-month HEP compared with the data before the HEP (Pafter the HEP (PAfter the 2-month HEP, the leg extensor muscle strength increased and the postural sway length on a foam surface decreased. The results indicate that the increased leg extensor muscle strength improves postural stability and diminishes the fear of falling in women with late-stage knee joint OA.

  20. The effects of performing a one-legged bridge with hip abduction and use of a sling on trunk and lower extremity muscle activation in healthy adults

    OpenAIRE

    Choi, Kyuju; Bak, Jongwoo; Cho, Minkwon; Chung, Yijung

    2016-01-01

    [Purpose] This study investigated the changes in the muscle activities of the trunk and lower limbs of healthy adults during a one-legged bridge exercise using a sling, and with the addition of hip abduction. [Subjects and Methods] Twenty-seven healthy individuals participated in this study (14 males and 13 females). The participants were instructed to perform the bridge exercises under five different conditions. Trunk and lower limb muscle activation of the erector spinae (ES), external obli...

  1. Contribution of Leg-Muscle Forces to Paddle Force and Kayak Speed During Maximal-Effort Flat-Water Paddling.

    Science.gov (United States)

    Nilsson, Johnny E; Rosdahl, Hans G

    2016-01-01

    The purpose was to investigate the contribution of leg-muscle-generated forces to paddle force and kayak speed during maximal-effort flat-water paddling. Five elite male kayakers at national and international level participated. The participants warmed up at progressively increasing speeds and then performed a maximal-effort, nonrestricted paddling sequence. This was followed after 5 min rest by a maximal-effort paddling sequence with the leg action restricted--the knee joints "locked." Left- and right-side foot-bar and paddle forces were recorded with specially designed force devices. In addition, knee angular displacement of the right and left knees was recorded with electrogoniometric technique, and the kayak speed was calculated from GPS signals sampled at 5 Hz. The results showed that reduction in both push and pull foot-bar forces resulted in a reduction of 21% and 16% in mean paddle-stroke force and mean kayak speed, respectively. Thus, the contribution of foot-bar force from lower-limb action significantly contributes to kayakers' paddling performance.

  2. The effects of a weight belt on trunk and leg muscle activity and joint kinematics during the squat exercise.

    Science.gov (United States)

    Zink, A J; Whiting, W C; Vincent, W J; McLaine, A J

    2001-05-01

    Fourteen healthy men participated in a study designed to examine the effects of weight-belt use on trunk- and leg-muscle myoelectric activity (EMG) and joint kinematics during the squat exercise. Each subject performed the parallel back squat exercise at a self-selected speed according to his own technique with 90% of his IRM both without a weight belt (NWB) and with a weight belt (WB). Myoelectric activity of the right vastus lateralis, biceps femoris, adductor magnus, gluteus maximus, and erector spinae was recorded using surface electrodes. Subjects were videotaped from a sagittal plane view while standing on a force plate. WB trials were completed significantly faster (p squat exercise may affect the path of the barbell and speed of the lift without altering myoelectric activity. This suggests that the use of a weight belt may improve a lifter's explosive power by increasing the speed of the movement without compromising the joint range of motion or overall lifting technique.

  3. Comparison of Abdominal Muscle Activity During a Single-Legged Hold in the Hook-Lying Position on the Floor and on a Round Foam Roll

    Science.gov (United States)

    Kim, Su-Jung; Kwon, Oh-Yun; Yi, Chung-Hwi; Jeon, Hye-Seon; Oh, Jae-Seop; Cynn, Heon-Seock; Weon, Jong-Hyuck

    2011-01-01

    Context: To improve trunk stability or trunk muscle strength, many athletic trainers and physiotherapists use various types of unstable equipment for training. The round foam roll is one of those unstable pieces of equipment and may be useful for improving trunk stability. Objective: To assess the effect of the supporting surface (floor versus round foam roll) on the activity of abdominal muscles during a single-legged hold exercise performed in the hook-lying position on the floor and on a round foam roll. Design: Crossover study. Setting: University research laboratory. Patients or Other Participants: Nineteen healthy volunteers (11 men, 8 women) from a university population. Interventions : The participants were instructed to perform a single-legged hold exercise while in the hook-lying position on the floor (stable surface) and on a round foam roll (unstable surface). Main Outcome Measure(s): Surface electromyography (EMG) signals were recorded from the bilateral rectus abdominis, internal oblique, and external oblique muscles. Dependent variables were examined with a paired t test. Results: The EMG activities in all abdominal muscles were greater during the single-legged hold exercise performed on the round foam roll than on the stable surface. Conclusions: The single-legged hold exercise in the hook-lying position on an unstable supporting surface induced greater abdominal muscle EMG amplitude than the same exercise performed on a stable supporting surface. These results suggest that performing the single-legged hold exercise while in the hook-lying position on a round foam roll is useful for activating the abdominal muscles. PMID:21944072

  4. Low appendicular skeletal muscle mass (ASM) with limited mobility and poor health outcomes in middle-aged African Americans.

    Science.gov (United States)

    Malmstrom, Theodore K; Miller, Douglas K; Herning, Margaret M; Morley, John E

    2013-09-01

    Recent efforts to provide a consensus definition propose that sarcopenia be considered a clinical syndrome associated with the loss of both skeletal muscle mass and muscle function that occurs with aging. Validation of sarcopenia definitions that include both low muscle mass and poor muscle function is needed. In the population-based African American Health (AAH) study (N = 998 at baseline/wave 1), muscle mass and mobility were evaluated in a clinical testing center in a subsample of N = 319 persons (ages 52-68) at wave 4 (2004). Muscle mass was measured using dual energy x-ray absorptiometry and mobility by a 6-min walk test and 4-m gait walk test. Height corrected appendicular skeletal mass (ASM; 9.0 ± 1.5 in n = 124 males, 8.3 ± 2.2 in n = 195 females) was computed as total lean muscle mass in arms and legs (kilograms) divided by the square of height (meters). Cross-sectional and longitudinal (6-year) associations of low ASM (bottom 25 % AAH sample; ASM with limited mobility (4-m gait walk ≤1 m/s or 6-min walk ASM with limited mobility was associated with IADL difficulties (p = .008) and frailty (p = .040) but not with ADL difficulties or falls in cross-sectional analyses; and with ADL difficulties (p = .022), IADL difficulties (p = .006), frailty (p = .039), and mortality (p = .003) but not with falls in longitudinal analyses adjusted for age and gender. Low ASM alone was marginally associated with mortality (p = .085) but not with other outcomes in cross-sectional or longitudinal analyses. Low ASM with limited mobility is associated with poor health outcomes among late middle-aged African Americans.

  5. Muscle hypertrophy: A narrative review on training principles for increasing muscle mass

    OpenAIRE

    Howe, Louis; Read, Paul; Waldron, Mark

    2017-01-01

    Developing muscle cross-sectional area has the potential to enhance performance for many athletes. Because emerging evidence challenges traditional beliefs regarding the prescription of hypertrophy-focused training programs, this review provides an overview of the current literature relating, specifically, to programming variables. Evidence-based recommendations are provided for the design of effective resistance-training programs, with the goal of increasing an athlete's skeletal muscle mass.

  6. Trunk and hip muscle recruitment patterns during the prone leg extension following a lateral ankle sprain: A prospective case study pre and post injury

    Directory of Open Access Journals (Sweden)

    Lehman Gregory J

    2006-02-01

    Full Text Available Abstract Background and case presentation The prone leg extension (PLE is commonly used to identify dysfunction of muscle recruitment patterns. The prone leg extension is theorized to identify proximal muscle disturbances which are a result of distal injury or dysfunction (i.e. an ankle sprain. This case study compares the trunk and hip muscle (bilateral lower erector spine, ipsilateral hamstring and ipsilateral gluteus maximus timing during a PLE of a 27 year old female runner during a healthy state (pre ankle sprain and 2 and 8 weeks post ankle sprain. Results and discussion The gluteus maximus muscle onsets at 8 weeks post injury appeared to occur earlier compared with 2 weeks post injury. The Right Erector Spinae at 8 weeks post injury was also active earlier compared with the participant's non-injured state. A large degree of variability can be noted within trials on the same day for all muscle groups. Conclusion An acute ankle injury did not result in a delay in gluteus maximus muscle activation. The utility of the prone leg extension as a clinical and functional test is questionable due to the normal variability seen during the test and our current inability to determine what is normal and what is dysfunctional.

  7. Trunk and hip muscle recruitment patterns during the prone leg extension following a lateral ankle sprain: A prospective case study pre and post injury

    Science.gov (United States)

    Lehman, Gregory J

    2006-01-01

    Background and case presentation The prone leg extension (PLE) is commonly used to identify dysfunction of muscle recruitment patterns. The prone leg extension is theorized to identify proximal muscle disturbances which are a result of distal injury or dysfunction (i.e. an ankle sprain). This case study compares the trunk and hip muscle (bilateral lower erector spine, ipsilateral hamstring and ipsilateral gluteus maximus) timing during a PLE of a 27 year old female runner during a healthy state (pre ankle sprain) and 2 and 8 weeks post ankle sprain. Results and discussion The gluteus maximus muscle onsets at 8 weeks post injury appeared to occur earlier compared with 2 weeks post injury. The Right Erector Spinae at 8 weeks post injury was also active earlier compared with the participant's non-injured state. A large degree of variability can be noted within trials on the same day for all muscle groups. Conclusion An acute ankle injury did not result in a delay in gluteus maximus muscle activation. The utility of the prone leg extension as a clinical and functional test is questionable due to the normal variability seen during the test and our current inability to determine what is normal and what is dysfunctional. PMID:16504168

  8. Response of the muscles in the pelvic floor and the lower lateral abdominal wall during the Active Straight Leg Raise in women with and without pelvic girdle pain: An experimental study.

    Science.gov (United States)

    Sjödahl, Jenny; Gutke, Annelie; Ghaffari, Ghazaleh; Strömberg, Tomas; Öberg, Birgitta

    2016-06-01

    The relationship between activation of the stabilizing muscles of the lumbopelvic region during the Active Straight Leg Raise test and pelvic girdle pain remains unknown. Therefore, the aim was to examine automatic contractions in relation to pre-activation in the muscles of the pelvic floor and the lower lateral abdominal wall during leg lifts, performed as the Active Straight Leg Raise test, in women with and without persistent postpartum pelvic girdle pain. Sixteen women with pelvic girdle pain and eleven pain-free women performed contralateral and ipsilateral leg lifts, while surface electromyographic activity was recorded from the pelvic floor and unilaterally from the lower lateral abdominal wall. As participants performed leg lifts onset time was calculated as the time from increased muscle activity to leg lift initiation. No significant differences were observed between the groups during the contralateral leg lift. During the subsequent ipsilateral leg lift, pre-activation in the pelvic floor muscles was observed in 36% of women with pelvic girdle pain and in 91% of pain-free women (P=0.01). Compared to pain-free women, women with pelvic girdle pain also showed significantly later onset time in both the pelvic floor muscles (P=0.01) and the muscles of the lower lateral abdominal wall (Pactivation patterns influence women's ability to stabilize the pelvis during leg lifts. This could be linked to provocation of pain during repeated movements. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Contribution of Leg Muscle Explosive Power and Eye-Hand Coordination to The Accuracy Smash of Athletes in Volleyball Club of Universitas Islam Riau

    Directory of Open Access Journals (Sweden)

    Mimi Yulianti

    2017-11-01

    Full Text Available The purpose of this study was to determine the contribution of leg muscle explosive power and eye-hand coordination. The type of research was correlational. The population in this study was all athletes who actively follow the training as many as 20 people and using total sampling technique. Thus the sample in this study amounted to 20 men athletes. The data were collected using the measurement test on the three variables: the leg muscle explosive power data was using vertical jump test, eyehand coordination was using ballwerfen und fangen test and smash accuracy was using smash accuracy test. The data were analyzed by product moment correlation and double correlation and then continued with contribution of the determinant formula. Based on data analysis found that there was contribution of leg muscle explosive power equal to 35,52%, eye-hand coordination equal to 20,79%, and both equal to 40,70% regarding to the accuracy smash of volleyball atletes of Universitas Islam Riau. It was concluded that there was contribution of leg muscle explosive power and eye-hand coordination to the smash accuracy of volleyball athlete of Universitas Islam Riau.

  10. Leg for life? The use of sartorius muscle flap for the treatment of an infected vascular reconstructions after VA-ECMO use. A case report

    Directory of Open Access Journals (Sweden)

    George V. Patrut

    2015-01-01

    Conclusion: Although ischemic complications associated with VA-ECMO are accepted by intensivists under the slogan “leg for life”, for the repair of the femoral artery in the presence of groin infection the sartorius muscle remains an efficient solution for limb salvage.

  11. The Effect of Intelligence, Leg Muscle Strength, and Balance Towards The Learning Outcomes of Pencak Silat with Empty-Handed Single Artistic

    Directory of Open Access Journals (Sweden)

    Aridhotul Haqiyah

    2017-10-01

    Full Text Available This study aims to Determine the effect of intelligence, leg muscle strength, as well as the balance towards the learning outcomes of pencak silat empty-handed single artistic on the Physical Education students of Islamic University 45 Bekasi. The research method is a survey, and the analysis technique is path analysis. This research held in Islamic University 45 Bekasi with 122 people of population. The sampling technique used is random sampling, then a sample of this research is 60 people. The instruments used are a rubric 4 scale (very good, good, enough and less of the learning outcomes of pencak silat emptyhanded single artistic, intelligence test with IST (Intelligent Structure Test, leg muscle strength with instrument squat test, and test of balance by using the modified bass test of dynamic balance. Based the result of the data processing and analysis, the Conclusions are: : (1 Intelligence directly effect on the learningoutcomes of pencak silat empty-handed single artistic with ρy1  = 0.359, (2 Leg muscles strength directlyeffect on the learning outcomes of pencak silat empty-handed single artistic with ρy2 = 0.228, (3 Balance directly effect on the learning outcomes of pencak silat empty-handed single artistic with ρy3 = 0.356, (4 Intelligence directly effects on the balance with ρ31 = 0.662, and (5 Leg muscle strength directly effectson the balance with ρ32 = 0.298.

  12. Muscle activity during the active straight leg raise (ASLR), and the effects of a pelvic belt on the ASLR and on treadmill walking

    NARCIS (Netherlands)

    Hu, H.; Meijer, O.G.; van Dieen, J.H.; Hodges, P.W.; Bruijn, S.M.; Strijers, R.L.M.; Nanayakkara, P.W.B.; van Royen, B.J.; Wu, W.H.; Xia, C.

    2010-01-01

    Women with pregnancy-related pelvic girdle pain (PPP), or athletes with groin pain, may have trouble with the active straight leg raise (ASLR), for which a pelvic belt can be beneficial. How the problems emerge, or how the belt works, remains insufficiently understood. We assessed muscle activity

  13. Repair of a soft tissue defect of medial malleolus with cross-leg bridge free transfer of anterolateral thigh muscle flap: a case report

    Directory of Open Access Journals (Sweden)

    ZHANG Gong-lin

    2012-11-01

    Full Text Available 【Abstract】A 38-year-old man sustained a traffic accident injury to his right medial malleolus and leg. It was an open fracture of the right tibia and fibula accompanied by a large soft tissue defect of the right medial malleolus sized 12 cm×4 cm. Doppler examination revealed that the tibialis posterior vessel was occluded due to thrombosis. The anterior tibial artery was patent. Three weeks after injury, the left anterolateral thigh muscle flap was harvested and transplanted to the right medial malleolus defect area for repair of the soft tissue defect, and an end-to-side anasto-mosis was performed between the posterior tibial vessel of the contralateral leg and the muscle flap’s vascular pedicle. A split thickness free skin graft was used to cover the muscle flap and around the flap’s vascular pedicle. The vascular pedicle was cut off after 28 days and the muscle flap sur-vived completely. After 3-year follow-up postoperatively, the right tibia and fibula fractures were confirmed healing radiologically. The posterior tibial artery of contralateral leg was patent by clinical and Doppler examinations. This tech-nique can be used to preserve the flow and patency of re-cipient arteries. Key words: Surgical flaps; Soft tissue injuries; Leg injuries; Wound healing

  14. Impact of a single session of intermittent pneumatic leg compressions on skeletal muscle and isolated artery gene expression in rats.

    Science.gov (United States)

    Roseguini, Bruno T; Arce-Esquivel, Arturo A; Newcomer, Sean C; Laughlin, M H

    2011-12-01

    Intermittent pneumatic leg compressions (IPC) have proven to be an effective noninvasive approach for treatment of patients with claudication, but the mechanisms underlying the clinical benefits remain elusive. In the present study, a rodent model of claudication produced by bilateral ligation of the femoral artery was used to investigate the acute impact of a single session of IPC (150 min) on hemodynamics, skeletal muscle (tibialis anterior), and isolated collateral artery (perforating artery) expression of a subset of genes associated with inflammation and vascular remodeling. In addition, the effect of compression frequency (15 vs. 3 compressions/min) on the expression of these factors was studied. In ligated animals, IPC evoked an increase of monocyte chemoattractant protein-1 (MCP-1) and cytokine-induced neutrophil chemoattractant 1 (CXCL1) mRNA (P < 0.01) and immunostaining (P < 0.05), as well as a minor increase in VEGF immunostaining in the muscle endomysium 150 min postintervention. Further, collateral arteries from these animals showed an increased expression of MCP-1 (approximately twofold, P = 0.02). These effects were most evident in the group exposed to the high-frequency protocol (15 compressions/min). In contrast, IPC in sham-operated control animals evoked a modest initial upregulation of VEGF (P = 0.01), MCP-1 (P = 0.02), and CXCL1 (P = 0.03) mRNA in the muscle without concomitant changes in protein levels. No changes in gene expression were observed in arteries isolated from sham animals. In conclusion, IPC acutely up-regulates the expression of important factors involved in vascular remodeling in the compressed muscle and collateral arteries in a model of hindlimb ischemia. These effects appear to be dependent on the compression frequency, such that a high compression frequency (15 compressions/min) evokes more consistent and robust effects compared with the frequency commonly employed clinically to treat patients with claudication (3

  15. The impact of low skeletal muscle mass in abdominal surgery

    NARCIS (Netherlands)

    J.L.A. van Vugt (Jeroen)

    2017-01-01

    textabstractAlthough perioperative outcome in transplant and surgical oncology patients has greatly improved during the last decades, preoperative risk assessment remains of utmost importance to further improve outcomes and adapt patient-tailored treatment strategies. Low skeletal muscle mass is

  16. Association between muscle mass and a single measurement of ...

    African Journals Online (AJOL)

    The relationship between muscle mass and a diagnosis of hypertension in a sample of Korean adults (N=225)was investigated. The participants included adults aged >20 years who visited the S-gu Public Health Centre, Seoul, Korea for a medical check-up in 2011. The Joint National Committee on Prevention, Detection, ...

  17. No Change of Body Mass, Fat Mass, and Skeletal Muscle Mass in Ultraendurance Swimmers after 12 Hours of Swimming

    Science.gov (United States)

    Knechtle, Beat; Knechtle, Patrizia; Kaul, Rene; Kohler, Gotz

    2009-01-01

    We evaluated whether ultraendurance swimmers suffer a change of body mass, fat mass, skeletal muscle mass, total body water, and specific gravity of urine during a 12-hr swim in 12 male Caucasian ultraswimmers. Proton nuclear magnetic resonance of urine samples before and after the race was performed to detect alanine, lactate, and…

  18. Baseline Muscle Mass Is a Poor Predictor of Functional Overload-Induced Gain in the Mouse Model.

    Science.gov (United States)

    Kilikevicius, Audrius; Bunger, Lutz; Lionikas, Arimantas

    2016-01-01

    Genetic background contributes substantially to individual variability in muscle mass. Muscle hypertrophy in response to resistance training can also vary extensively. However, it is less clear if muscle mass at baseline is predictive of the hypertrophic response. The aim of this study was to examine the effect of genetic background on variability in muscle mass at baseline and in the adaptive response of the mouse fast- and slow-twitch muscles to overload. Males of eight laboratory mouse strains: C57BL/6J (B6, n = 17), BALB/cByJ ( n = 7), DBA/2J (D2, n = 12), B6.A-( rs3676616-D10Utsw1 )/Kjn (B6.A, n = 9), C57BL/6J-Chr10 A/J /NaJ (B6.A10, n = 8), BEH+/+ ( n = 11), BEH ( n = 12), and DUHi ( n = 12), were studied. Compensatory growth of soleus and plantaris muscles was triggered by a 4-week overload induced by synergist unilateral ablation. Muscle weight in the control leg (baseline) varied from 5.2 ± 07 mg soleus and 11.4 ± 1.3 mg plantaris in D2 mice to 18.0 ± 1.7 mg soleus in DUHi and 43.7 ± 2.6 mg plantaris in BEH ( p muscles). In addition, soleus in the B6.A10 strain was ~40% larger ( p muscle weight, however, the extent of gain was strain-dependent for both soleus ( p muscle, the BEH strain emerged as the least responsive, with a 1.3-fold increase, compared to a 1.7-fold gain in the most responsive D2 strain, and there was no difference in the gain between the B6.A10 and B6 strains. The BEH strain appeared the least responsive in the gain of plantaris as well, 1.3-fold, compared to ~1.5-fold gain in the remaining strains. We conclude that variation in muscle mass at baseline is not a reliable predictor of that in the overload-induced gain. This suggests that a different set of genes influence variability in muscle mass acquired in the process of normal development, growth, and maintenance, and in the process of adaptive growth of the muscle challenged by overload.

  19. Baseline muscle mass is a poor predictor of functional overload-induced gain in the mouse model

    Directory of Open Access Journals (Sweden)

    Audrius Kilikevicius

    2016-11-01

    Full Text Available Genetic background contributes substantially to individual variability in muscle mass. Muscle hypertrophy in response to resistance training can also vary extensively. However, it is less clear if muscle mass at baseline is predictive of the hypertrophic response.The aim of this study was to examine the effect of genetic background on variability in muscle mass at baseline and in the adaptive response of the mouse fast- and slow-twitch muscles to overload. Males of eight laboratory mouse strains: C57BL/6J (B6, n=17, BALB/cByJ (n=7, DBA/2J (D2, n=12, B6.A-(rs3676616-D10Utsw1/Kjn (B6.A, n=9, C57BL/6J-Chr10A/J/NaJ (B6.A10, n=8, BEH+/+ (n=11, BEH (n=12 and DUHi (n=12, were studied. Compensatory growth of soleus and plantaris muscles was triggered by a 4-week overload induced by synergist unilateral ablation. Muscle weight in the control leg (baseline varied from 5.2±07 mg soleus and 11.4±1.3 mg plantaris in D2 mice to 18.0±1.7 mg soleus in DUHi and 43.7±2.6 mg plantaris in BEH (p<0.001 for both muscles. In addition, soleus in the B6.A10 strain was ~40% larger (p<0.001 compared to the B6. Functional overload increased muscle weight, however, the extent of gain was strain-dependent for both soleus (p<0.01 and plantaris (p<0.02 even after accounting for the baseline differences. For the soleus muscle, the BEH strain emerged as the least responsive, with a 1.3-fold increase, compared to a 1.7-fold gain in the most responsive D2 strain, and there was no difference in the gain between the B6.A10 and B6 strains. The BEH strain appeared the least responsive in the gain of plantaris as well, 1.3-fold, compared to ~1.5-fold gain in the remaining strains. We conclude that variation in muscle mass at baseline is not a reliable predictor of that in the overload-induced gain. This suggests that a different set of genes influence variability in muscle mass acquired in the process of normal development, growth and maintenance, and in the process of adaptive

  20. Bilateral idiopathic calf muscle hypertrophy: an exceptional cause of unsightly leg curvature.

    Science.gov (United States)

    Herlin, C; Chaput, B; Rivier, F; Doucet, J C; Bigorre, M; Captier, G

    2015-04-01

    The authors present the management of a young female patient who presented with longstanding bilateral calf muscle hypertrophy, with no known cause. Taking into account the patient's wishes and the fact that the hypertrophy was mainly located in the posteromedial compartment, we chose to carry out a subtotal bilateral resection of medial gastrocnemius muscles. This procedure was performed with an harmonic scalpel, permitting a excellent cosmetic result while avoiding complications or functional impairment. After a reviewing of the commonly used techniques, the authors discuss the chosen surgical approach taking into account its clinical particularity. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  1. Bilateral motor unit synchronization of leg muscles during a simple dynamic balance task

    NARCIS (Netherlands)

    Boonstra, T.W.; Daffertshofer, A.; Roerdink, M.; Flipse, I.; Groenewoud, K.; Beek, P.J.

    2009-01-01

    To handle the rich repertoire of behavioural goals, the CNS has to control the many degrees of freedom of the musculoskeletal system in a flexible manner. This problem can be drastically simplified if muscle synergies serve as the to-be-controlled building blocks of motor performance, instead of the

  2. The Regulation of Muscle Mass by Endogenous Glucocorticoids

    Directory of Open Access Journals (Sweden)

    Daniel L Marks

    2015-02-01

    Full Text Available Glucocorticoids are highly conserved fundamental regulators of energy homeostasis. In response to stress in the form of perceived danger or acute inflammation, glucocorticoids are released from the adrenal gland, rapidly mobilizing energy from carbohydrate, fat and protein stores. In the case of inflammation, mobilized protein is critical for the rapid synthesis of acute phase reactants and an efficient immune response to infection. While adaptive in response to infection, chronic mobilization can lead to a p rofound depletion of energy stores. Skeletal muscle represents the major body store of protein, and can become substantially atrophied under conditions of chronic inflammation. Glucocorticoids elicit the atrophy of muscle by increasing the rate of protein degradation by the ubiquitin-proteasome system and autophagy lysosome system. Protein synthesis is also suppressed at the level of translational initiation, preventing the production of new myofibrillar protein. Glucocorticoids also antagonize the action of anabolic regulators such as insulin further exacerbating the loss of protein and muscle mass. The loss of muscle mass in the context of chronic disease is a key feature of cachexia and contributes substantially to morbidity and mortality. A growing body of evidence demonstrates that glucocorticoid signaling is a common mediator of wasting, irrespective of the underlying initiator or disease state. This review will highlight fundamental mechanisms of glucocorticoid signaling and detail the mechanisms of glucocorticoid-induced muscle atrophy. Additionally, the evidence for glucocorticoids as a driver of muscle wasting in numerous disease states will be discussed. Given the burden of wasting diseases and the nodal nature of glucocorticoid signaling, effective anti-glucocorticoid therapy would be a valuable clinical tool. Therefore, the progress and potential pitfalls in the development of glucocorticoid antagonists for muscle wasting will

  3. The influence of foot position on lower leg muscle activity during a heel raise exercise measured with fine-wire and surface EMG.

    Science.gov (United States)

    Akuzawa, Hiroshi; Imai, Atsushi; Iizuka, Satoshi; Matsunaga, Naoto; Kaneoka, Koji

    2017-11-01

    Exercises for lower leg muscles are important to improve function. To examine the influence of foot position on lower leg muscle activity during heel raises. Cross-sectional laboratory study. Laboratory. Fourteen healthy men participated in this study. The muscle activity levels of the tibialis posterior (TP), peroneus longus (PL), flexor digitorum longus (FDL) and medial gastrocnemius (MG) were measured. The heel raises consisted of three foot positions: 1) neutral, 2) 30° abduction, and 3) 30° adduction. The EMG data for five repetitions of each foot position were normalized to maximum voluntary contraction. One-way repeated measure ANOVA was employed for statistical analysis. The muscle activity level of TP, PL and FDL was significantly different between the three foot positions during the heel raises. TP and FDL showed the highest activity level in 30° foot adduction while PL demonstrated the highest activity level in 30° foot abduction. Heel raises with 30° foot adduction and abduction positions can change lower leg muscle activity; These findings suggest that altering foot posture during the heel raise exercise may benefit patients with impaired TP, PL or FDL function. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Muscle activity and spine load during anterior chain whole body linkage exercises: the body saw, hanging leg raise and walkout from a push-up.

    Science.gov (United States)

    McGill, Stuart; Andersen, Jordan; Cannon, Jordan

    2015-01-01

    This study examined anterior chain whole body linkage exercises, namely the body saw, hanging leg raise and walkout from a push-up. Investigation of these exercises focused on which particular muscles were challenged and the magnitude of the resulting spine load. Fourteen males performed the exercises while muscle activity, external force and 3D body segment motion were recorded. A sophisticated and anatomically detailed 3D model used muscle activity and body segment kinematics to estimate muscle force, and thus sensitivity to each individual's choice of motor control for each task. Gradations of muscle activity and spine load characteristics were observed across tasks. On average, the hanging straight leg raise created approximately 3000 N of spine compression while the body saw created less than 2500 N. The hanging straight leg raise created the highest challenge to the abdominal wall (>130% MVC in rectus abdominis, 88% MVC in external oblique). The body saw resulted in almost 140% MVC activation of the serratus anterior. All other exercises produced substantial abdominal challenge, although the body saw did so in the most spine conserving way. These findings, along with consideration of an individual's injury history, training goals and current fitness level, should assist in exercise choice and programme design.

  5. Changes in lower extremity muscle mass and muscle strength after weight loss in obese patients with knee osteoarthritis

    DEFF Research Database (Denmark)

    Henriksen, Marius; Christensen, Robin; Danneskiold-Samsøe, Bente

    2012-01-01

    To investigate the effects of low-energy diet-induced weight loss on lower-extremity muscle mass and knee muscle strength in obese patients with knee osteoarthritis (OA), and the associations of these effects.......To investigate the effects of low-energy diet-induced weight loss on lower-extremity muscle mass and knee muscle strength in obese patients with knee osteoarthritis (OA), and the associations of these effects....

  6. T₂ mapping provides multiple approaches for the characterization of muscle involvement in neuromuscular diseases: a cross-sectional study of lower leg muscles in 5-15-year-old boys with Duchenne muscular dystrophy.

    Science.gov (United States)

    Arpan, Ishu; Forbes, Sean C; Lott, Donovan J; Senesac, Claudia R; Daniels, Michael J; Triplett, William T; Deol, Jasjit K; Sweeney, H Lee; Walter, Glenn A; Vandenborne, Krista

    2013-03-01

    Skeletal muscles of children with Duchenne muscular dystrophy (DMD) show enhanced susceptibility to damage and progressive lipid infiltration, which contribute to an increase in the MR proton transverse relaxation time (T₂). Therefore, the examination of T₂ changes in individual muscles may be useful for the monitoring of disease progression in DMD. In this study, we used the mean T₂, percentage of elevated pixels and T₂ heterogeneity to assess changes in the composition of dystrophic muscles. In addition, we used fat saturation to distinguish T₂ changes caused by edema and inflammation from fat infiltration in muscles. Thirty subjects with DMD and 15 age-matched controls underwent T₂ -weighted imaging of their lower leg using a 3-T MR system. T₂ maps were developed and four lower leg muscles were manually traced (soleus, medial gastrocnemius, peroneal and tibialis anterior). The mean T₂ of the traced regions of interest, width of the T₂ histograms and percentage of elevated pixels were calculated. We found that, even in young children with DMD, lower leg muscles showed elevated mean T₂, were more heterogeneous and had a greater percentage of elevated pixels than in controls. T₂ measures decreased with fat saturation, but were still higher (P tissue in children with DMD, even in the early stages of the disease. Therefore, T₂ mapping may prove to be clinically useful in the monitoring of muscle changes caused by the disease process or by therapeutic interventions in DMD. Copyright © 2012 John Wiley & Sons, Ltd.

  7. Rhesus leg muscle EMG activity during a foot pedal pressing task on Bion 11

    Science.gov (United States)

    Hodgson, J. A.; Riazansky, S. N.; Goulet, C.; Badakva, A. M.; Kozlovskaya, I. B.; Recktenwald, M. R.; McCall, G.; Roy, R. R.; Fanton, J. W.; Edgerton, V. R.

    2000-01-01

    Rhesus monkeys (Macaca mulatta) were trained to perform a foot lever pressing task for a food reward. EMG activity was recorded from selected lower limb muscles of 2 animals before, during, and after a 14-day spaceflight and from 3 animals during a ground-based simulation of the flight. Integrated EMG activity was calculated for each muscle during the 20-min test. Comparisons were made between data recorded before any experimental manipulations and during flight or flight simulation. Spaceflight reduced soleus (Sol) activity to 25% of preflight levels, whereas it was reduced to 50% of control in the flight simulation. During flight, medial gastrocnemius (MG) activity was reduced to 25% of preflight activity, whereas the simulation group showed normal activity levels throughout all tests. The change in MG activity was apparent in the first inflight recording, suggesting that some effect of microgravity on MG activity was immediate.

  8. Intermittent pneumatic leg compressions enhance muscle performance and blood flow in a model of peripheral arterial insufficiency.

    Science.gov (United States)

    Roseguini, Bruno T; Arce-Esquivel, Arturo A; Newcomer, Sean C; Yang, Hsiao T; Terjung, Ronald; Laughlin, M H

    2012-05-01

    Despite the escalating prevalence in the aging population, few therapeutic options exist to treat patients with peripheral arterial disease. Application of intermittent pneumatic leg compressions (IPC) is regarded as a promising noninvasive approach to treat this condition, but the clinical efficacy, as well the mechanistic basis of action of this therapy, remain poorly defined. We tested the hypothesis that 2 wk of daily application of IPC enhances exercise tolerance by improving blood flow and promoting angiogenesis in skeletal muscle in a model of peripheral arterial insufficiency. Male Sprague-Dawley rats were subjected to bilateral ligation of the femoral artery and randomly allocated to treatment or sham groups. Animals were anesthetized daily and exposed to 1-h sessions of bilateral IPC or sham treatment for 14-16 consecutive days. A third group of nonligated rats was also studied. Marked increases in treadmill exercise tolerance (∼33%, P < 0.05) and improved muscle performance in situ (∼10%, P < 0.05) were observed in IPC-treated animals. Compared with sham-treated controls, blood flow measured with isotope-labeled microspheres during in situ contractions tended to be higher in IPC-treated animals in muscles composed of predominantly fast-twitch white fibers, such as the plantaris (∼93%, P = 0.02). Capillary contacts per fiber and citrate synthase activity were not significantly altered by IPC treatment. Collectively, these data indicate that IPC improves exercise tolerance in a model of peripheral arterial insufficiency in part by enhancing blood flow to collateral-dependent tissues.

  9. The effect of age and unilateral leg immobilization for 2 weeks on substrate utilization during moderate‐intensity exercise in human skeletal muscle

    Science.gov (United States)

    Gram, M.; Dybboe, R.; Kuhlman, A. B.; Prats, C.; Greenhaff, P. L.; Constantin‐Teodosiu, D.; Birk, J. B.; Wojtaszewski, J. F. P.; Dela, F.; Helge, J. W.

    2016-01-01

    Key points This study aimed to provide molecular insight into the differential effects of age and physical inactivity on the regulation of substrate metabolism during moderate‐intensity exercise.Using the arteriovenous balance technique, we studied the effect of immobilization of one leg for 2 weeks on leg substrate utilization in young and older men during two‐legged dynamic knee‐extensor moderate‐intensity exercise, as well as changes in key proteins in muscle metabolism before and after exercise.Age and immobilization did not affect relative carbohydrate and fat utilization during exercise, but the older men had higher uptake of exogenous fatty acids, whereas the young men relied more on endogenous fatty acids during exercise.Using a combined whole‐leg and molecular approach, we provide evidence that both age and physical inactivity result in intramuscular lipid accumulation, but this occurs only in part through the same mechanisms. Abstract Age and inactivity have been associated with intramuscular triglyceride (IMTG) accumulation. Here, we attempt to disentangle these factors by studying the effect of 2 weeks of unilateral leg immobilization on substrate utilization across the legs during moderate‐intensity exercise in young (n = 17; 23 ± 1 years old) and older men (n = 15; 68 ± 1 years old), while the contralateral leg served as the control. After immobilization, the participants performed two‐legged isolated knee‐extensor exercise at 20 ± 1 W (∼50% maximal work capacity) for 45 min with catheters inserted in the brachial artery and both femoral veins. Biopsy samples obtained from vastus lateralis muscles of both legs before and after exercise were used for analysis of substrates, protein content and enzyme activities. During exercise, leg substrate utilization (respiratory quotient) did not differ between groups or legs. Leg fatty acid uptake was greater in older than in young men, and although young men demonstrated net

  10. Muscle ion transporters and antioxidative proteins have different adaptive potential in arm than in leg skeletal muscle with exercise training

    DEFF Research Database (Denmark)

    Mohr, Magni; Nielsen, Tobias Schmidt; Weihe, Pál

    2017-01-01

    It was evaluated whether upper-body compared to lower-body musculature exhibits a different phenotype in relation to capacity for handling reactive oxygen species (ROS), H(+), La(-), Na(+), K(+) and also whether it differs in adaptive potential to exercise training. Eighty-three sedentary...... premenopausal women aged 45 ± 6 years (mean ± SD) were randomized into a high-intensity intermittent swimming group (HIS, n = 21), a moderate-intensity swimming group (MOS, n = 21), a soccer group (SOC, n = 21), or a control group (CON, n = 20). Intervention groups completed three weekly training sessions...... for 15 weeks, and pre- and postintervention biopsies were obtained from deltoideus and vastus lateralis muscle. Before training, monocarboxylate transporter 4 (MCT4), Na(+)/K(+) pump α2, and superoxide dismutase 2 (SOD2) expressions were lower (P

  11. Venogram - leg

    Science.gov (United States)

    Phlebogram - leg; Venography - leg; Angiogram - leg ... into a vein in the foot of the leg being looked at. An intravenous (IV) line is ... vein. A tourniquet may be placed on your leg so the dye flows into the deeper veins. ...

  12. Association of nutrition and immune-endocrine dysfunction with muscle mass and performance in cognitively impaired older adults.

    Science.gov (United States)

    Tay, L; Leung, B P; Wee, S; Tay, K S; Ali, N; Chan, M; Lim, W S

    With lean mass declining early in Alzheimer's disease, muscle quality beyond quantity is relevant to physical performance. We sought to identify potentially modifiable factors for the differential loss of muscle mass (pre-sarcopenia) and its performance (sarcopenia) in older adults with mild cognitive impairment (MCI) and mild-to-moderate Alzheimer's disease (AD). This is a cross-sectional study of 108 community-dwelling older adults with MCI and mild-to-moderate AD. Participants were categorized as: (i) No sarcopenia (normal muscle mass), (ii) Pre-sarcopenia (low muscle mass without weakness or slowness), (iii) Sarcopenia (low muscle mass AND weak grip strength and/or slow gait speed) using Asian cut-offs. Muscle quality was defined as the ratio of grip and knee extension strength to average arm and leg lean mass respectively. We measured cognitive, functional and physical (Short Physical Performance Battery, SPPB) performance; physical activity level; nutritional status; and blood biomarkers of inflammation and endocrine dysfunction. SPPB (p=0.033) and activity level (p=0.010) were highest in the pre-sarcopenic group. Pre-sarcopenic group had highest arm muscle quality [10.6 (7.7-12.2) vs 13.9 (12.6-15.7) vs 11.3 (9.7-12.8), p<0.001], despite significantly lower appendicular lean mass than non-sarcopenic group. In multi-nomial logistic regression reference to non-sarcopenic group, malnutrition independently increased risk for both pre-sarcopenia (Relative risk=7.53, 95% C.I 1.20-47.51, p=0.032) and sarcopenia (Relative risk=11.91, 95% C.I 2.85-49.77, p=0.001). A combined pro-inflammatory and endocrine deficient state significantly increased the risk of sarcopenia (Relative risk=5.17, 95% C.I 1.31-20.37, p=0.019). Malnutrition is a precursor for progressive loss of muscle mass, but a pro-inflammatory and endocrine deficient state may potentially aggravate decline in muscle quality to culminate in frank sarcopenia. Copyright © 2017 Elsevier B.V. All rights

  13. Hemodynamic responses to small muscle mass exercise in heart failure patients with reduced ejection fraction

    Science.gov (United States)

    Barrett-O'Keefe, Zachary; Lee, Joshua F.; Berbert, Amanda; Witman, Melissa A. H.; Nativi-Nicolau, Jose; Stehlik, Josef; Richardson, Russell S.

    2014-01-01

    To better understand the mechanisms responsible for exercise intolerance in heart failure with reduced ejection fraction (HFrEF), the present study sought to evaluate the hemodynamic responses to small muscle mass exercise in this cohort. In 25 HFrEF patients (64 ± 2 yr) and 17 healthy, age-matched control subjects (64 ± 2 yr), mean arterial pressure (MAP), cardiac output (CO), and limb blood flow were examined during graded static-intermittent handgrip (HG) and dynamic single-leg knee-extensor (KE) exercise. During HG exercise, MAP increased similarly between groups. CO increased significantly (+1.3 ± 0.3 l/min) in the control group, but it remained unchanged across workloads in HFrEF patients. At 15% maximum voluntary contraction (MVC), forearm blood flow was similar between groups, while HFrEF patients exhibited an attenuated increase at the two highest intensities compared with controls, with the greatest difference at the highest workload (352 ± 22 vs. 492 ± 48 ml/min, HFrEF vs. control, 45% MVC). During KE exercise, MAP and CO increased similarly across work rates between groups. However, HFrEF patients exhibited a diminished leg hyperemic response across all work rates, with the most substantial decrement at the highest intensity (1,842 ± 64 vs. 2,675 ± 81 ml/min; HFrEF vs. control, 15 W). Together, these findings indicate a marked attenuation in exercising limb perfusion attributable to impairments in peripheral vasodilatory capacity during both arm and leg exercise in patients with HFrEF, which likely plays a role in limiting exercise capacity in this patient population. PMID:25260608

  14. Diagnostic ultrasound estimates of muscle mass and muscle quality discriminate between women with and without sarcopenia

    Directory of Open Access Journals (Sweden)

    Catheeja eIsmail

    2015-10-01

    Full Text Available Introduction: Age-related changes in muscle mass and muscle tissue composition contribute to diminished strength in older adults. The objectives of this study are to examine if an assessment method using mobile diagnostic ultrasound augments well-known determinants of lean body mass (LBM to aid sarcopenia staging, and if a sonographic measure of muscle quality is associated with muscle performance.Methods: Twenty community-dwelling female subjects participated in the study (age = 43.4 ±20.9 years; BMI: 23.8, interquartile range: 8.5. Dual energy X-ray absorptiometry (DXA and diagnostic ultrasound morphometry were used to estimate LBM. Muscle tissue quality was estimated via the echogenicity using grayscale histogram analysis. Peak force was measured with grip dynamometry and scaled for body size. Bivariate and multiple regression analyses were used to determine the association of the predictor variables with appendicular lean mass (aLM/ht2, and examine the relationship between scaled peak force values and muscle echogenicity. The sarcopenia LBM cut point value of 6.75 kg/m2 determined participant assignment into the Normal LBM and Low LBM subgroups.Results: The selected LBM predictor variables were body mass index (BMI, ultrasound morphometry, and age. Although BMI exhibited a significant positive relationship with aLM/ht2 (adj. R2 = .61, p < .001, the strength of association improved with the addition of ultrasound morphometry and age as predictor variables (adj. R2 = .85, p < .001. Scaled peak force was associated with age and echogenicity (adj. R2 = .53, p < .001, but not LBM. The Low LBM subgroup of women (n = 10 had higher scaled peak force, lower BMI, and lower echogenicity values in comparison to the Normal LBM subgroup (n = 10; p < .05.Conclusions: Diagnostic ultrasound morphometry values are associated with LBM, and improve the BMI predictive model for aLM/ht2 in women. In addition, ultrasound proxy measures of muscle quality are more

  15. Effect of amino acid supplementation on muscle mass, strength and physical function in elderly.

    Science.gov (United States)

    Børsheim, Elisabet; Bui, Quynh-Uyen T; Tissier, Sandrine; Kobayashi, Hisamine; Ferrando, Arny A; Wolfe, Robert R

    2008-04-01

    With advancing age there is a gradual decline in muscle mass, strength and function. The aim of this study was to determine if regular intake of a nutritional supplement containing essential amino acids (EAA)+arginine could reverse these responses in elderly subjects. Twelve glucose intolerant subjects (67.0+/-5.6 (SD) years, 7 females, 5 males) ingested 11 g of EAA+arginine two times a day, between meals for 16 weeks. Diet and activity were not otherwise modified. Lean body mass (DEXA) was measured every fourth week. Maximal leg strength was tested and functional tests were performed at week 0, 8, 12, and 16. Lean body mass (LBM) increased during the study (p=0.038). At week 12, the average increase in LBM was 1.14+/-0.36 (SE) kg (pvs baseline), whereas at week 16, the increase was 0.60+/-0.38 kg (NS vs baseline). The lower extremity strength measure score (sum of individual knee flexors and extensors' one repetition maximum, n=10) was 127.5+/-21.8 kg at baseline, and average increase during the study was 22.2+/-6.1% (pspeed (p=0.002), timed 5-step test (p=0.007), and timed floor-transfer test (p=0.022). Supplementation of the diet with EAA+arginine improves lean body mass, strength and physical function compared to baseline values in glucose intolerant elderly individuals.

  16. Childhood development of common drive to a human leg muscle during ankle dorsiflexion and gait

    DEFF Research Database (Denmark)

    Hvass Petersen, Tue; Kliim-Due, Mette; Farmer, Simon F.

    2010-01-01

    Corticospinal drive has been shown to contribute significantly to the control of walking in adult human subjects. It is unknown to what an extent functional change in this drive is important for maturation of gait in children. In adults, populations of motor units within a muscle show synchronized...... discharges during walking with pronounced coherence in the 15-50 Hz frequency band. This coherence has been shown to depend on cortical drive. Here, we investigated how this coherence changes with development. 44 healthy children aged 4 - 15 yrs participated in the study. Electromyographic activity (EMG...

  17. Does peroperative external pneumatic leg muscle compression prevent post-operative venous thrombosis in neurosurgery?

    Science.gov (United States)

    Bynke, O; Hillman, J; Lassvik, C

    1987-01-01

    Post-operative deep venous thrombosis (DVT) is a frequent and potentially life-threatening complication in neurosurgery. In this field of surgery, with its special demands for exact haemostasis, prophylaxis against deep venous thrombosis with anticoagulant drugs has been utilized only reluctantly. Postoperative pneumatic muscle compression (EPC) has been shown to be effective, although there are several practical considerations involved with this method which limit its clinical applicability. In the present study per-operative EPC was evaluated and was found to provide good protection against DVT in patients with increased risk from this complication. This method has the advantage of being effective, safe, inexpensive and readily practicable.

  18. Improvement in upper leg muscle strength underlies beneficial effects of exercise therapy in knee osteoarthritis: secondary analysis from a randomised controlled trial.

    Science.gov (United States)

    Knoop, J; Steultjens, M P M; Roorda, L D; Lems, W F; van der Esch, M; Thorstensson, C A; Twisk, J W R; Bierma-Zeinstra, S M A; van der Leeden, M; Dekker, J

    2015-06-01

    Although exercise therapy is effective for reducing pain and activity limitations in patients with knee osteoarthritis (OA), the underlying mechanisms are unclear. This study aimed to evaluate if improvements in neuromuscular factors (i.e. upper leg muscle strength and knee proprioception) underlie the beneficial effects of exercise therapy in patients with knee OA. Secondary analyses from a randomised controlled trial, with measurements at baseline, 6 weeks, 12 weeks and 38 weeks. Rehabilitation centre. One hundred and fifty-nine patients diagnosed with knee OA. Exercise therapy. Changes in pain [numeric rating scale (NRS)] and activity limitations [Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) physical function subscale and get-up-and-go test] during the study period. Independent variables were changes in upper leg muscle strength and knee joint proprioception (i.e. motion sense) during the study period. Longitudinal regression analyses (generalised estimating equation) were performed to analyse associations between changes in upper leg muscle strength and knee proprioception with changes in pain and activity limitations. Improved muscle strength was significantly associated with reductions in NRS pain {B coefficient -2.5 [95% confidence interval (CI) -3.7 to -1.4], meaning that every change of 1 unit of strength was linked to a change of -2.5 units of pain}, WOMAC physical function (-8.8, 95% CI -13.4 to -4.2) and get-up-and-go test (-1.7, 95% CI -2.4 to -1.0). Improved proprioception was not significantly associated with better outcomes of exercise therapy (P>0.05). Upper leg muscle strengthening is one of the mechanisms underlying the beneficial effects of exercise therapy in patients with knee OA. Copyright © 2014 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.

  19. Lower limb muscle pre-motor time measures during a choice reaction task associate with knee abduction loads during dynamic single leg landings.

    Science.gov (United States)

    McLean, Scott G; Borotikar, Bhushan; Lucey, Sarah M

    2010-07-01

    Female neuromuscular control during dynamic landings is considered central to their increased ACL injury risk relative to males. There is limited insight, however, into the neuromuscular parameters governing this risk, which may hinder prevention success. This study targeted a new screenable and potentially trainable neuromuscular risk factor. Specifically, we examined whether lower limb muscle pre-motor times, being the time between stimulus presentation and initiation of the muscle EMG burst, elicited during a simple choice reaction task correlated with knee abduction loads during separate single leg landings. Twenty female NCAA athletes had muscle (n=8) pre-motor time and knee biomechanics data recorded bilaterally during a choice reaction task. Knee biomechanics were also quantified during anticipated and unanticipated single (dominant and non-dominant) leg landings. Mean peak knee abduction loads during landings were submitted to a two-way ANOVA to test for limb and decision effects. Individual regression coefficients were initially computed between-limb-based muscle pre-motor times and peak abduction moments elicited during both the choice reaction and landing tasks. Limb-based linear stepwise regression coefficients were also computed between muscle PMT's demonstrating significant (Pmuscle pre-motor times during a specific choice reaction task are associated with peak knee abduction loads during separate single leg landings. These muscles appear critical in stabilizing the knee against the extreme dynamic load states associated with such tasks. Targeted screening and training of supraspinal processes governing these muscle pre-motor times may ultimately enable external knee loads associated with landings to be more effectively countered by the overarching neuromuscular strategy. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  20. Effect of Feedback Corrective Exercise on Knee Valgus and Electromyographic Activity of Lower Limb Muscles in Single Leg Squat

    Directory of Open Access Journals (Sweden)

    Negar Koorosh-fard

    2015-07-01

    Full Text Available Objective: The aim of this study was assessing the effect of feedback correcting exercise in front of mirror during running on frontal plane knee and pelvic kinematic and electromyography activity of some lower extremity muscles in single leg squat (SLS. Materials & Methods: This study was quasi experimental. 23 active female subjects participated in two experimental and control groups with mean age (21.86± 2.43 years .experimental group contains subjects with knee valgus and pelvic drop angle more than a mean plus one standard deviation of the population in functional SLS. Muscular activity (RMS of gluteus maximus, Gluteus medius, rectus femoris, vastus medialis, vastus lateralis, biceps femoris and semitendinosus, angle of knee valgus and pelvic drop were register in end of SLS Pre and post of 8 training sessions. Comparing Variable has done with independent t statistical test between 2 groups and pair sample t test within each groups with significant level of 0.05. Results: Statistical analysis Before training showed no significant differences in pelvic drop between two groups (P&ge0.05, but knee valgus angle was significantly more than control group (P&le0.05. In spit that most muscle activities (% MVC except biceps femoris (P&le0.05, were greater in experimental group, no significant difference (P&ge0.05 has seen in two groups. Comparing pre and post test has showed no significant difference in knee valgus of experimental group, however it decreased around 2 degrees and although %MVC decreased in all muscles, just rectuse femoris has shown significant difference (P&le0.05. No significant difference has seen in control group in all variables (P&ge0.05. Conclusion: Findings showed poor neuromuscular control in experimental group which improved to some extent after training because lower muscle activity and energy consumption in specific movement with similar kinematic indicate improvement of motor control or cause learning. It seems that

  1. A Tricuspid Valve Mass Attached to Papillary Muscle.

    Science.gov (United States)

    Sabzi, Feridoun; Ghasemi, Fahimeh; Asadmobini, Atefeh

    2016-05-01

    Cardiac myxoma is the most common benign heart tumor which can arise in any of the cardiac chambers, valves or related great veins. Diagnosis of a myxoma arising from the tricuspid valve apparatus is exceptional. We present a rare case of myxoma in a tricuspid valve attached to papillary muscle. A 45-year-old man was referred to our center for the evaluation dyspnea and chest pain. During work-up by transthoracic echocardiography (TTE), a mass was found on the corda tendinea of the anterior papillary muscle of the tricuspid valve. Coronary angiography revealed normal coronary artery. During open heart surgery, an oval and non-pedunculated mass was detected on tricuspid corda tendinea and resected. Pathological examination revealed the presence of a myxoma. This experience illustrates a rare case of myxoma which originated from tricuspid corda tendinea, diagnosed by echocardiography, suggesting fibroelastoma. However, the mass was not clear enough but dyspnea and sign and symptom of probably embolization to lung urged us to treat it surgically. No complications attributable to the mass developed in the postoperative course. In the first year of follow-up, non-recurrence of the mass was detected on TEE, and the patient was asymptomatic.

  2. Chronic impairment of leg muscle blood flow following cardiac catheterization in childhood

    International Nuclear Information System (INIS)

    Skovranek, J.; Samanek, M.

    1979-01-01

    In 99 patients with congenital heart defects or chronic respiratory disease without clinical symptoms of disturbances in peripheral circulation, resting and maximal blood flow in the anterior tibial muscle of both extremities were investigated 2.7 yrs (average) after cardiac catheterization. The method used involved 133 Xe clearance. Resting blood flow was normal and no difference could be demonstrated between the extremity originally used for catheterization and the contralateral control extremity. No disturbance in maximal blood flow could be proved in the extremity used for catheterization by the venous route only. Maximal blood flow was significantly lower in that extremity where the femoral artery had been catheterized or cannulated for pressure measurement and blood sampling. The disturbance in maximal flow was shown regardless of whether the arterial catheterization involved the Seldinger percutaneous technique, arteriotomy, or mere cannulation of the femoral artery. The values in the involved extremity did not differ significantly from the values in a healthy population

  3. Leg muscle reflexes mediated by cutaneous A-beta fibres are normal during gait in reflex sympathetic dystrophy.

    Science.gov (United States)

    van der Laan, L; Boks, L M; van Wezel, B M; Goris, R J; Duysens, J E

    2000-04-01

    Reflex sympathetic dystrophy (RSD) is, from the onset, characterized by various neurological deficits such as an alteration of sensation and a decrease in muscle strength. We investigated if afferent A-beta fibre-mediated reflexes are changed in lower extremities affected by acute RSD. The involvement of these fibres was determined by analyzing reflex responses from the tibialis anterior (TA) and biceps femoris (BF) muscles after electrical stimulation of the sural nerve. The reflexes were studied during walking on a treadmill to investigate whether the abnormalities in gait of the patients were related either to abnormal amplitudes or deficient phase-dependent modulation of reflexes. In 5 patients with acute RSD of the leg and 5 healthy volunteers these reflex responses were determined during the early and late swing phase of the step cycle. No significant difference was found between the RSD and the volunteers. During early swing the mean amplitude of the facilitatory P2 responses in BF and TA increased as a function of stimulus intensity (1.5, 2 and 2.5 times the perception threshold) in both groups. At end swing the same stimuli induced suppressive responses in TA. This phase-dependent reflex reversal from facilitation in early swing to suppression in late swing occurred equally in both groups. In the acute phase of RSD of the lower extremity there is no evidence for abnormal A-beta fibre-mediated reflexes or for defective regulation of such reflexes. This finding has implications for both the theory on RSD pathophysiology and RSD models, which are based on abnormal functioning of A-beta fibres.

  4. Smoking cessation-related weight gain--beneficial effects on muscle mass, strength and bone health.

    Science.gov (United States)

    Rom, Oren; Reznick, Abraham Z; Keidar, Zohar; Karkabi, Khaled; Aizenbud, Dror

    2015-02-01

    To examine the effects of smoking cessation on body composition and muscle strength in comparison with continued smoking. Twelve-month longitudinal study of adult smokers conducted in Haifa, Israel. Eighty-one smokers recruited from a smoking cessation programme combining group counselling and varenicline treatment. Measurements were taken at the beginning of the programme and after 12 months. Body composition was assessed by dual-energy X-ray absorptiometry. Muscle strength was measured by handgrip dynamometry and predicted one-repetition maximum tests. Dietary intake and physical activity levels were estimated using questionnaires. Smoking status was determined by urine cotinine. The effect of smoking cessation was assessed using univariate and multivariable linear regression analyses. Forty-one participants (age 44 ± 12 years) completed all baseline and follow-up measurements (76% continued smokers; 24% quitters). All measures of body composition and muscle strength were increased among quitters when compared with continued smokers. Adjusted differences [95% confidence interval (CI)] between quitters and smokers were: body weight 4.43 kg (1.56-7.31 kg); lean mass 1.26 kg (0.24-2.28 kg); fat mass 3.15 kg (0.91-5.39 kg); bone mineral content 48.76 g (12.06-85.54 g); bone mineral density 0.024 g/cm(2) (0.004-0.043 g/cm(2) ); handgrip strength 3.6 kg (1.12-6.08 kg); predicted one-repetition maximum of chest press 7.85 kg (1.93-13.76 kg); and predicted one-repetition maximum of leg press 17.02 kg (7.29-26.75 kg). Smoking cessation is associated with weight gain mainly through accumulating extra fat, but is also associated with increased muscle mass, muscle strength and bone density. © 2014 Society for the Study of Addiction.

  5. The adipokine leptin increases skeletal muscle mass and significantly alters skeletal muscle miRNA expression profile in aged mice

    International Nuclear Information System (INIS)

    Hamrick, Mark W.; Herberg, Samuel; Arounleut, Phonepasong; He, Hong-Zhi; Shiver, Austin; Qi, Rui-Qun; Zhou, Li; Isales, Carlos M.

    2010-01-01

    Research highlights: → Aging is associated with muscle atrophy and loss of muscle mass, known as the sarcopenia of aging. → We demonstrate that age-related muscle atrophy is associated with marked changes in miRNA expression in muscle. → Treating aged mice with the adipokine leptin significantly increased muscle mass and the expression of miRNAs involved in muscle repair. → Recombinant leptin therapy may therefore be a novel approach for treating age-related muscle atrophy. -- Abstract: Age-associated loss of muscle mass, or sarcopenia, contributes directly to frailty and an increased risk of falls and fractures among the elderly. Aged mice and elderly adults both show decreased muscle mass as well as relatively low levels of the fat-derived hormone leptin. Here we demonstrate that loss of muscle mass and myofiber size with aging in mice is associated with significant changes in the expression of specific miRNAs. Aging altered the expression of 57 miRNAs in mouse skeletal muscle, and many of these miRNAs are now reported to be associated specifically with age-related muscle atrophy. These include miR-221, previously identified in studies of myogenesis and muscle development as playing a role in the proliferation and terminal differentiation of myogenic precursors. We also treated aged mice with recombinant leptin, to determine whether leptin therapy could improve muscle mass and alter the miRNA expression profile of aging skeletal muscle. Leptin treatment significantly increased hindlimb muscle mass and extensor digitorum longus fiber size in aged mice. Furthermore, the expression of 37 miRNAs was altered in muscles of leptin-treated mice. In particular, leptin treatment increased the expression of miR-31 and miR-223, miRNAs known to be elevated during muscle regeneration and repair. These findings suggest that aging in skeletal muscle is associated with marked changes in the expression of specific miRNAs, and that nutrient-related hormones such as leptin

  6. The adipokine leptin increases skeletal muscle mass and significantly alters skeletal muscle miRNA expression profile in aged mice

    Energy Technology Data Exchange (ETDEWEB)

    Hamrick, Mark W., E-mail: mhamrick@mail.mcg.edu [Department of Cellular Biology and Anatomy, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA (United States); Department of Orthopaedic Surgery, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA (United States); Herberg, Samuel; Arounleut, Phonepasong [Department of Cellular Biology and Anatomy, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA (United States); Department of Orthopaedic Surgery, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA (United States); He, Hong-Zhi [Henry Ford Immunology Program, Henry Ford Health System, Detroit, MI (United States); Department of Dermatology, Henry Ford Health System, Detroit, MI (United States); Shiver, Austin [Department of Cellular Biology and Anatomy, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA (United States); Department of Orthopaedic Surgery, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA (United States); Qi, Rui-Qun [Henry Ford Immunology Program, Henry Ford Health System, Detroit, MI (United States); Department of Dermatology, Henry Ford Health System, Detroit, MI (United States); Zhou, Li [Henry Ford Immunology Program, Henry Ford Health System, Detroit, MI (United States); Department of Dermatology, Henry Ford Health System, Detroit, MI (United States); Department of Internal Medicine, Henry Ford Health System, Detroit, MI (United States); Isales, Carlos M. [Department of Cellular Biology and Anatomy, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA (United States); Department of Orthopaedic Surgery, Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA (United States); and others

    2010-09-24

    Research highlights: {yields} Aging is associated with muscle atrophy and loss of muscle mass, known as the sarcopenia of aging. {yields} We demonstrate that age-related muscle atrophy is associated with marked changes in miRNA expression in muscle. {yields} Treating aged mice with the adipokine leptin significantly increased muscle mass and the expression of miRNAs involved in muscle repair. {yields} Recombinant leptin therapy may therefore be a novel approach for treating age-related muscle atrophy. -- Abstract: Age-associated loss of muscle mass, or sarcopenia, contributes directly to frailty and an increased risk of falls and fractures among the elderly. Aged mice and elderly adults both show decreased muscle mass as well as relatively low levels of the fat-derived hormone leptin. Here we demonstrate that loss of muscle mass and myofiber size with aging in mice is associated with significant changes in the expression of specific miRNAs. Aging altered the expression of 57 miRNAs in mouse skeletal muscle, and many of these miRNAs are now reported to be associated specifically with age-related muscle atrophy. These include miR-221, previously identified in studies of myogenesis and muscle development as playing a role in the proliferation and terminal differentiation of myogenic precursors. We also treated aged mice with recombinant leptin, to determine whether leptin therapy could improve muscle mass and alter the miRNA expression profile of aging skeletal muscle. Leptin treatment significantly increased hindlimb muscle mass and extensor digitorum longus fiber size in aged mice. Furthermore, the expression of 37 miRNAs was altered in muscles of leptin-treated mice. In particular, leptin treatment increased the expression of miR-31 and miR-223, miRNAs known to be elevated during muscle regeneration and repair. These findings suggest that aging in skeletal muscle is associated with marked changes in the expression of specific miRNAs, and that nutrient

  7. Excitability changes in the left primary motor cortex innervating the hand muscles induced during speech about hand or leg movements.

    Science.gov (United States)

    Onmyoji, Yusuke; Kubota, Shinji; Hirano, Masato; Tanaka, Megumi; Morishita, Takuya; Uehara, Kazumasa; Funase, Kozo

    2015-05-06

    In the present study, we used transcranial magnetic stimulation (TMS) to investigate the changes in the excitability of the left primary motor cortex (M1) innervating the hand muscles and in short-interval intracortical inhibition (SICI) during speech describing hand or leg movements. In experiment 1, we investigated the effects of the contents of speech on the amplitude of the motor evoked potentials (MEPs) induced during reading aloud and silent reading. In experiment 2, we repeated experiment 1 with an additional condition, the non-vocal oral movement (No-Voc OM) condition, and investigated the change in SICI induced in each condition using the paired TMS paradigm. The MEP observed in the reading aloud and No-Voc OM conditions exhibited significantly greater amplitudes than those seen in the silent reading conditions, irrespective of the content of the sentences spoken by the subjects or the timing of the TMS. There were no significant differences in SICI between the experimental conditions. Our findings suggest that the increased excitability of the left M1 hand area detected during speech was mainly caused by speech-related oral movements and the activation of language processing-related brain functions. The increased left M1 excitability was probably also mediated by neural mechanisms other than reduced SICI; i.e., disinhibition. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  8. Effect of body mass index and fat mass on balance force platform measurements during a one-legged stance in older adults.

    Science.gov (United States)

    Pereira, Camila; Silva, Rubens A da; de Oliveira, Marcio R; Souza, Rejane D N; Borges, Renata J; Vieira, Edgar R

    2017-07-05

    The purpose of this study was to evaluate the impact of body mass index (BMI) and fat mass on balance force platform measurements in older adults. The sample consisted of 257 participants who were stratified into four groups by BMI: low weight, normal weight, pre-obesity and obesity. For fat mass variables, older individuals were classified into low and high-fat mass. All groups investigated performed three trials of one-legged stance balance on a force platform. Center of pressure (COP) domain parameters were computed from the mean across trials. Analysis of variance results revealed no significant interactions for groups and sexes for all COP parameters. Comparable balance results were found for BMI and fat groups for all COP parameters. A statistical effect (P COP parameters, regardless of BMI and fat mass variables. Overall, women presented better balance than men. In conclusion, BMI and fat mass do not seem to influence the balance of older adults during a one-leg stance task.

  9. Reliability of MR-Based Volumetric 3-D Analysis of Pelvic Muscles among Subjects with Low Back with Leg Pain and Healthy Volunteers

    Science.gov (United States)

    Skorupska, Elżbieta; Keczmer, Przemysław; Łochowski, Rafał M.; Tomal, Paulina; Rychlik, Michał; Samborski, Włodzimierz

    2016-01-01

    Aim Lately, the diagnostic value of magnetic resonance imaging, Lasègue sign and classic neurological signs have been considered not accurate enough to distinguish the radicular from non-radicular low back with leg pain (LBLP) and a calculation of the symptomatic side muscle volume has been indicated as a probable valuable marker. However, only the multifidus muscle volume has been calculated so far. The main objective of the study was to verify whether LBLP subjects presented symptomatic side pelvic muscle atrophy compared to healthy volunteers. The second aim was to assess the inter-rater reliability of 3-D manual method for segmenting and measuring the volume of the gluteus maximus, gluteus medius, gluteus minimus and piriformis muscles in both LBLP patients and healthy subjects. Method Two independent raters analyzed MR images of LBLP and healthy subjects towards muscle volume of four pelvic muscles, i.e. the piriformis, gluteus minimus, gluteus medius and gluteus maximus. For both sides, the MR images of the muscles without adipose tissue infiltration were manually segmented in 3-D medical images. Results Symptomatic muscle atrophy was confirmed in only over 50% of LBLP subjects (gluteus maximus (pgluteus minimus (pgluteus medius muscle in LBLP patients, which was equal to 0.848. Conclusion More than 50% of LBLP subjects presented symptomatic gluteus maximus, gluteus minimus and piriformis muscle atrophy. 3-D manual segmentation reliably measured muscle volume in all the measured pelvic muscles in both healthy and LBLP subjects. To answer the question of what kind of muscle atrophy is indicative of radicular or non-radicular pain further studies are required. PMID:27459688

  10. Reliability of MR-Based Volumetric 3-D Analysis of Pelvic Muscles among Subjects with Low Back with Leg Pain and Healthy Volunteers.

    Directory of Open Access Journals (Sweden)

    Elżbieta Skorupska

    Full Text Available Lately, the diagnostic value of magnetic resonance imaging, Lasègue sign and classic neurological signs have been considered not accurate enough to distinguish the radicular from non-radicular low back with leg pain (LBLP and a calculation of the symptomatic side muscle volume has been indicated as a probable valuable marker. However, only the multifidus muscle volume has been calculated so far. The main objective of the study was to verify whether LBLP subjects presented symptomatic side pelvic muscle atrophy compared to healthy volunteers. The second aim was to assess the inter-rater reliability of 3-D manual method for segmenting and measuring the volume of the gluteus maximus, gluteus medius, gluteus minimus and piriformis muscles in both LBLP patients and healthy subjects.Two independent raters analyzed MR images of LBLP and healthy subjects towards muscle volume of four pelvic muscles, i.e. the piriformis, gluteus minimus, gluteus medius and gluteus maximus. For both sides, the MR images of the muscles without adipose tissue infiltration were manually segmented in 3-D medical images.Symptomatic muscle atrophy was confirmed in only over 50% of LBLP subjects (gluteus maximus (p<0.001, gluteus minimus (p<0.01 and piriformis (p<0.05. The ICC values indicated that the inter-rater reproducibility was greater than 0.90 for all measurements (LBLP and healthy subjects, except for the measurement of the right gluteus medius muscle in LBLP patients, which was equal to 0.848.More than 50% of LBLP subjects presented symptomatic gluteus maximus, gluteus minimus and piriformis muscle atrophy. 3-D manual segmentation reliably measured muscle volume in all the measured pelvic muscles in both healthy and LBLP subjects. To answer the question of what kind of muscle atrophy is indicative of radicular or non-radicular pain further studies are required.

  11. It is not just muscle mass: a review of muscle quality, composition and metabolism during ageing as determinants of muscle function and mobility in later life.

    Science.gov (United States)

    McGregor, Robin A; Cameron-Smith, David; Poppitt, Sally D

    2014-01-01

    Worldwide estimates predict 2 billion people will be aged over 65 years by 2050. A major current challenge is maintaining mobility and quality of life into old age. Impaired mobility is often a precursor of functional decline, disability and loss of independence. Sarcopenia which represents the age-related decline in muscle mass is a well-established factor associated with mobility limitations in older adults. However, there is now evidence that not only changes in muscle mass but other factors underpinning muscle quality including composition, metabolism, aerobic capacity, insulin resistance, fat infiltration, fibrosis and neural activation may also play a role in the decline in muscle function and impaired mobility associated with ageing. Importantly, changes in muscle quality may precede loss of muscle mass and therefore provide new opportunities for the assessment of muscle quality particularly in middle-aged adults who could benefit from interventions to improve muscle function. This review will discuss the accumulating evidence that in addition to muscle mass, factors underpinning muscle quality influence muscle function and mobility with age. Further development of tools to assess muscle quality in community settings is needed. Preventative diet, exercise or treatment interventions particularly in middle-aged adults at the low end of the spectrum of muscle function may help preserve mobility in later years and improve healthspan.

  12. Acute impact of intermittent pneumatic leg compression frequency on limb hemodynamics, vascular function, and skeletal muscle gene expression in humans.

    Science.gov (United States)

    Sheldon, Ryan D; Roseguini, Bruno T; Thyfault, John P; Crist, Brett D; Laughlin, M H; Newcomer, Sean C

    2012-06-01

    The mechanisms by which intermittent pneumatic leg compression (IPC) treatment effectively treats symptoms associated with peripheral artery disease remain speculative. With the aim of gaining mechanistic insight into IPC treatment, the purpose of this study was to investigate the effect of IPC frequency on limb hemodynamics, vascular function, and skeletal muscle gene expression. In this two study investigation, healthy male subjects underwent an hour of either high-frequency (HF; 2-s inflation/3-s deflation) or low-frequency (LF; 4-s inflation/16-s deflation) IPC treatment of the foot and calf. In study 1 (n = 11; 23.5 ± 4.7 yr), subjects underwent both HF and LF treatment on separate days. Doppler/ultrasonography was used to measure popliteal artery diameter and blood velocity at baseline and during IPC treatment. Flow-mediated dilation (FMD) and peak reactive hyperemia blood flow (RHBF) were determined before and after IPC treatment. In study 2 (n = 19; 22.0 ± 4.6 yr), skeletal muscle biopsies were taken from the lateral gastrocnemius of the treated and control limb at baseline and at 30- and 150-min posttreatment. Quantitative PCR was used to assess mRNA concentrations of genes associated with inflammation and vascular remodeling. No treatment effect on vascular function was observed. Cuff deflation resulted in increased blood flow (BF) and shear rate (SR) in both treatments at the onset of treatment compared with baseline (P < 0.01). BF and SR significantly diminished by 45 min of HF treatment only (P < 0.01). Both treatments reduced BF and SR and elevated oscillatory shear index compared with baseline (P < 0.01) during cuff inflation. IPC decreased the mRNA expression of cysteine-rich protein 61 from baseline and controls (P <0 .01) and connective tissue growth factor from baseline (P < 0.05) in a frequency-dependent manner. In conclusion, a single session of IPC acutely impacts limb hemodynamics and skeletal muscle gene expression in a frequency

  13. mTOR as a Key Regulator in Maintaining Skeletal Muscle Mass

    OpenAIRE

    Yoon, Mee-Sup

    2017-01-01

    Maintenance of skeletal muscle mass is regulated by the balance between anabolic and catabolic processes. Mammalian target of rapamycin (mTOR) is an evolutionarily conserved serine/threonine kinase, and is known to play vital roles in protein synthesis. Recent findings have continued to refine our understanding of the function of mTOR in maintaining skeletal muscle mass. mTOR controls the anabolic and catabolic signaling of skeletal muscle mass, resulting in the modulation of muscle hypertrop...

  14. Comparing the amount of EMG activity of the selected involved muscles in ankle strategy in female athletes while standing on one leg on shuttle balance and wobble board

    Directory of Open Access Journals (Sweden)

    Mansouri R

    2015-05-01

    Full Text Available Abstract Background: It seems that using shuttle balance which has recently been produced in Iran would be beneficial in exercise prescription for preventing sports injuries and recovery. The purpose of this study is comparing the amount of the electromyography activity of involved muscles in ankle strategy while standing on one leg on shuttle balance versus wobble board. Materials and Methods: this study is a functional and cause-compare study. 15 female students 20-22 years of age having the enterance standards were selected meaningfully. The amount of EMG activity of selected muscles (Tibialis Anterior, Gastrocnemius, Rectus Femoris and Hamstring was measured while standing on one leg on two devices. The difference in means of muscles activity in both of devices was estimated using multivariate analysis of variance. Results: The results showed a significant difference between the amount of EMG activity of involved muscles (p=0.001. Also, the results of the intragroup effects showed that the electromyography activity of Tibialis Anterior, Rectus Femoris and Hamstring while standing on shuttle balance was significantly more than the activity while standing on wobble board (p0/05. Conclusion: It seems that standing on shuttle balance can make higher electromyography activity in the muscles that are involved on ankle and thigh joints, i.e. Tibialis Anterior, Rectus Femoris and Hamstring. So it is recommended that shuttle balance can be used in balance training program.

  15. Higher Protein Intake Is Associated with Higher Lean Mass and Quadriceps Muscle Strength in Adult Men and Women.

    Science.gov (United States)

    Sahni, Shivani; Mangano, Kelsey M; Hannan, Marian T; Kiel, Douglas P; McLean, Robert R

    2015-07-01

    The impact of dietary protein intake on lower extremity lean mass and strength in community-dwelling adult Americans is not fully understood. The objective was to determine the associations between total protein (TP), animal protein (AP), and plant protein (PP) intakes and lean mass of the legs and quadriceps muscle strength. We further examined whether the associations with quadriceps strength may be explained by lean mass of the legs. This cross-sectional study included men (n = 1166) and women (n = 1509) from the Framingham Offspring Cohort in Massachusetts. Protein intake in grams per day was measured in either 1995-1998 or 1998-2001. Leg lean mass and isometric quadriceps strength, both in kilograms, were measured in 1996-2001. Multilinear regression models estimated adjusted least squares means of each of the muscle measures by quartile categories of protein intake, adjusting for relevant confounders and covariates. Mean age was 59 ± 9 y (range: 29-86 y) and TP intake was 80 ± 27 g/d in men and 76 ± 26 g/d in women. In men and women, leg lean mass was higher in participants in the highest quartiles of TP and AP intake compared with those in the lowest quartiles of intake [least squares means (kg): TP-17.6 vs. 17.1 in men, P-trend: 0.005, and 11.7 vs. 11.4 in women, P-trend: 0.006; AP-17.6 vs. 17.1 in men, P-trend: 0.002, and 11.7 vs. 11.4 in women, P-trend: 0.003]. PP intake was not associated with lean mass in either sex. In men and women, quadriceps strength was higher in participants in the highest quartile of PP intake compared with those in the lowest quartile [least squares means (kg): 22.9 vs. 21.7 in men, P-trend: 0.01, and 19.0 vs. 18.2 in women, P-trend: 0.01]; this association was no longer significant after adjustment for fruit and vegetable intake (P-trend: 0.06 in men and 0.10 in women). Although no significant association was observed for AP intake in either sex, nonsignificant protective trends were observed for TP intake (P-trend: 0.08 in

  16. Appendicular Skeletal Muscle Mass Reference Values and the Peak Muscle Mass to Identify Sarcopenia among Iranian Healthy Population.

    Science.gov (United States)

    Shafiee, Gita; Ostovar, Afshin; Heshmat, Ramin; Keshtkar, Abbas Ali; Sharifi, Farshad; Shadman, Zhaleh; Nabipour, Iraj; Soltani, Akbar; Larijani, Bagher

    2018-01-01

    Sacopenia is a common problem in elderly with the adverse outcomes. The objective of this study was to estimate the peak appendicular skeletal muscle mass (ASM) and age of its attainment by sex among the Iranian population. A total of 691 men and women aged 18-94 years participated in this cross-sectional, population-based study in Bushehr, Iran. ASM was measured by dual X-ray absorptiometry. Cutoff points for men and women were established considering two standard deviations (SDs) below the mean values of the skeletal muscle index (SMI) for young reference groups. The relationship between ASM and age was described by the second-degree regression models. Two SDs below the mean SMIs of reference groups were as cutoff values of low muscle mass in Iranian population. The peak ASM values were 21.35 ± 0.12 Kg and 13.68 ± 0.10 Kg, and the age at peak ASM were 26 (24-28) years and 34 (33-35) years for men and women, respectively. Mean and SD of SMI in those ages were 7.01 ± 0.02 Kg/m 2 and 5.44 ± 0.02 Kg/m 2 among men and women, respectively. Calculated cutoff values of low muscle mass among the Iranian population were 7.0 Kg/m 2 and 5.4 Kg/m 2 among men and women, respectively. Iranian reference values of SMI for both genders were similar to Asia Working Group for Sarcopenia recommendation and lower than the United States and European values. Further studies from different nations and the Middle East countries are needed to obtain reference values for populations, enabling the researchers for comparison and also more valid reports on sarcopenia prevalence.

  17. Comparison of muscle/lean mass measurement methods: correlation with functional and biochemical testing.

    Science.gov (United States)

    Buehring, B; Siglinsky, E; Krueger, D; Evans, W; Hellerstein, M; Yamada, Y; Binkley, N

    2018-03-01

    DXA-measured lean mass is often used to assess muscle mass but has limitations. Thus, we compared DXA lean mass with two novel methods-bioelectric impedance spectroscopy and creatine (methyl-d3) dilution. The examined methodologies did not measure lean mass similarly and the correlation with muscle biomarkers/function varied. Muscle function tests predict adverse health outcomes better than lean mass measurement. This may reflect limitations of current mass measurement methods. Newer approaches, e.g., bioelectric impedance spectroscopy (BIS) and creatine (methyl-d3) dilution (D3-C), may more accurately assess muscle mass. We hypothesized that BIS and D3-C measured muscle mass would better correlate with function and bone/muscle biomarkers than DXA measured lean mass. Evaluations of muscle/lean mass, function, and serum biomarkers were obtained in older community-dwelling adults. Mass was assessed by DXA, BIS, and orally administered D3-C. Grip strength, timed up and go, and jump power were examined. Potential muscle/bone serum biomarkers were measured. Mass measurements were compared with functional and serum data using regression analyses; differences between techniques were determined by paired t tests. Mean (SD) age of the 112 (89F/23M) participants was 80.6 (6.0) years. The lean/muscle mass assessments were correlated (.57-.88) but differed (p Lean mass measures were unrelated to the serum biomarkers measured. These three methodologies do not similarly measure muscle/lean mass and should not be viewed as being equivalent. Functional tests assessing maximal muscle strength/power (grip strength and jump power) correlated with all mass measures whereas gait speed was not. None of the selected serum measures correlated with mass. Efforts to optimize muscle mass assessment and identify their relationships with health outcomes are needed.

  18. Soluble Milk Proteins Improve Muscle Mass Recovery after Immobilization-Induced Muscle Atrophy in Old Rats but Do not Improve Muscle Functional Property Restoration.

    Science.gov (United States)

    Verney, J; Martin, V; Ratel, S; Chavanelle, V; Bargetto, M; Etienne, M; Chaplais, E; Le Ruyet, P; Bonhomme, C; Combaret, L; Guillet, C; Boisseau, N; Sirvent, P; Dardevet, D

    2017-01-01

    Effect of 3 different dairy protein sources on the recovery of muscle function after limb immobilization in old rats. Longitudinal animal study. Institut National de la Recherche Agronomique (INRA). The study took part in a laboratory setting. Old rats were subjected to unilateral hindlimb immobilization for 8 days and then allowed to recover with 3 different dietary proteins: casein, soluble milk proteins or whey proteins for 49 days. Body weight, muscle mass, muscle fibre size, isometric, isokinetic torque, muscle fatigability and muscle oxidative status were measured before and at the end of the immobilization period and during the recovery period i.e 7, 21, 35 and 49 days post immobilization. In contrast to the casein diet, soluble milk proteins and whey proteins were efficient to favor muscle mass recovery after cast immobilization during aging. By contrast, none of the 3 diary proteins was able to improve muscle strength, power and fatigability showing a discrepancy between the recovery of muscle mass and function. However, the soluble milk proteins allowed a better oxidative capacity in skeletal muscle during the rehabilitation period. Whey proteins and soluble milk proteins improve muscle mass recovery after immobilization-induced muscle atrophy in old rats but do not allow muscle functional property restoration.

  19. A Tricuspid Valve Mass Attached to Papillary Muscle

    OpenAIRE

    Sabzi, Feridoun; Ghasemi, Fahimeh; Asadmobini, Atefeh

    2016-01-01

    Background Cardiac myxoma is the most common benign heart tumor which can arise in any of the cardiac chambers, valves or related great veins. Diagnosis of a myxoma arising from the tricuspid valve apparatus is exceptional. We present a rare case of myxoma in a tricuspid valve attached to papillary muscle. Case Details A 45-year-old man was referred to our center for the evaluation dyspnea and chest pain. During work-up by transthoracic echocardiography (TTE), a mass was found on the corda te...

  20. Relationship of interleukin-6 and tumor necrosis factor-alpha with muscle mass and muscle strength in elderly men and women : the Health ABC Study

    NARCIS (Netherlands)

    Visser, Marjolein; Pahor, Marco; Taaffe, Dennis R; Goodpaster, Bret H; Simonsick, Eleanor M; Newman, Anne B; Nevitt, Michael; Harris, Tamara B

    BACKGROUND: A decline in muscle mass and muscle strength characterizes normal aging. As clinical and animal studies show a relationship between higher cytokine levels and low muscle mass, the aim of this study was to investigate whether markers of inflammation are associated with muscle mass and

  1. Effect of Body Mass Index on Postural Balance and Muscle Strength in Children Aged 8-10 years

    Directory of Open Access Journals (Sweden)

    Lucky Prasetiowati

    2017-04-01

    Full Text Available Background:Childhood overweight and obesity, which are considered as global epidemic, can be assessed using Body Mass Index (BMI. BMI difference can lead to anatomic changes due to an increased body load. This increase might also affect motor performance, including changes in postural balance and muscle strength. Aims and Objectives: to explain the influence of BMI on postural balance and lower limb muscle strength and to assess the correlation between those two variables in children aged 8-10 years. Material and methods:The sample consisted of 63 children aged 8-10 years, which were divided in 3 groups: BMI-normal, BMI-overweight, and BMI-obese. The postural balance was assessed using single leg balance test on MatScan and the Center Of Pressure (COP area was recorded. Isometric muscle strength of hip extensor and knee extensor were measured using a hand-held dynamometer. Results: Obese children had significantly largerCOP area than overweight (p = 0.004 and normal weight children (p = 0.000.There were no significant differences in hip extensor muscle strength between obese children with overweight and normal weight children (p=0.527. The absolute knee extensor muscle strength in obese group was significantly higher than the overweight and normal group (p = 0.003. However the relative muscle strength of lower limb for obese children was significantly lower than for normal weight. There was no significant correlation between absolute hip extensor and knee extensor muscles strength with COP area. Conclusion: Obese children have decreased postural balance and increased absolute knee extensormuscle strength significantly when compared to overweight and normal children. There is no significant correlation between postural balance and muscle strength.

  2. Age-related differences in lean mass, protein synthesis and skeletal muscle markers of proteolysis after bed rest and exercise rehabilitation.

    Science.gov (United States)

    Tanner, Ruth E; Brunker, Lucille B; Agergaard, Jakob; Barrows, Katherine M; Briggs, Robert A; Kwon, Oh Sung; Young, Laura M; Hopkins, Paul N; Volpi, Elena; Marcus, Robin L; LaStayo, Paul C; Drummond, Micah J

    2015-09-15

    Bed rest-induced muscle loss and impaired muscle recovery may contribute to age-related sarcopenia. It is unknown if there are age-related differences in muscle mass and muscle anabolic and catabolic responses to bed rest. A secondary objective was to determine if rehabilitation could reverse bed rest responses. Nine older and fourteen young adults participated in a 5-day bed rest challenge (BED REST). This was followed by 8 weeks of high intensity resistance exercise (REHAB). Leg lean mass (via dual-energy X-ray absorptiometry; DXA) and strength were determined. Muscle biopsies were collected during a constant stable isotope infusion in the postabsorptive state and after essential amino acid (EAA) ingestion on three occasions: before (PRE), after bed rest and after rehabilitation. Samples were assessed for protein synthesis, mTORC1 signalling, REDD1/2 expression and molecular markers related to muscle proteolysis (MURF1, MAFBX, AMPKα, LC3II/I, Beclin1). We found that leg lean mass and strength decreased in older but not younger adults after bedrest (P protein synthesis increased before bed rest in both age groups (P protein synthesis rates and increased MAFBX mRNA, p-AMPKα and the LC3II/I ratio (P muscle loss after short-term bed rest. This may be partially explained by a combined suppression of protein synthesis and a marginal increase in proteolytic markers. Finally, rehabilitation restored bed rest-induced deficits in lean mass and strength in older adults. © 2015 The Authors. The Journal of Physiology © 2015 The Physiological Society.

  3. The relationship of force output characteristics during a sit-to-stand movement with lower limb muscle mass and knee joint extension in the elderly.

    Science.gov (United States)

    Yamada, Takayoshi; Demura, Shinichi

    2010-01-01

    This study examined the reliability of ground reaction force (GRF) parameters during sit-to-stand (STS) movements and the relationships between the GRF parameters and lower limb muscle mass and knee extension muscle strength. Fifty elderly females performed an STS movement twice from a chair adjusted to their knee height and the GRF, lower limb muscle mass and isometric knee extension muscle strength were measured. Reliabilities of GRF parameters were high (intra-class correlation coefficient=ICC=0.70-0.95). Parameters on force output during trunk flexion phase (ground reaction force at hip-lift off, sum of force output between beginning of STS movement and hip-lift off) differed significantly between trials, but their effect sizes were small (0.15-0.23). GRF parameters during hip-lift off and knee-hip joint extension phases significantly correlated with knee extension strength (|r|=0.29-0.64) but not lower limb muscle mass. In conclusion, the reliability of GRF during STS movement is good in hip-lift off and knee-hip joint extension phases and these phases relate significantly with lower limb muscle function. These two phases are useful for evaluation of leg muscle function of the elderly. Copyright (c) 2009 Elsevier Ireland Ltd. All rights reserved.

  4. The Influence of Dual Pressure Biofeedback Units on Pelvic Rotation and Abdominal Muscle Activity during the Active Straight Leg Raise in Women with Chronic Lower Back Pain.

    Science.gov (United States)

    Noh, Kyung-Hee; Kim, Ji-Won; Kim, Gyoung-Mo; Ha, Sung-Min; Oh, Jae-Seop

    2014-05-01

    [Purpose] This study was performed to assess the influence of applying dual pressure biofeedback units (DPBUs) on the angle of pelvic rotation and abdominal muscle activity during the active straight leg raise (ASLR). [Subjects] Seventeen patients with low-back pain (LBP) participated in this study. [Methods] The subjects were asked to perform an active straight leg raise (ASLR) without a PBU, with a single PBU, and with DPBUs. The angles of pelvic rotation were measured using a three-dimensional motion-analysis system, and the muscle activity of the bilateral internal oblique abdominis (IO), external oblique abdominis (EO), and rectus abdominis (RA) was recorded using surface electromyography (EMG). One-way repeated-measures ANOVA was performed to determine the rotation angles and muscle activity under the three conditions. [Results] The EMG activity of the ipsilateral IO, contralateral EO, and bilateral RA was greater and pelvic rotation was lower with the DPBUs than with no PBU or a single PBU. [Conclusion] The results of this study suggest that applying DPBUs during ASLR is effective in decreasing unwanted pelvic rotation and increasing abdominal muscle activity in women with chronic low back pain.

  5. An Integrated Low-Volume Nutritional Countermeasure to Maintain Muscle Mass and Function During Space Exploration

    Data.gov (United States)

    National Aeronautics and Space Administration — Mechanical unloading, an inherent characteristic of spaceflight, results in a loss of muscle mass and muscle strength. These losses threaten the integrity of space...

  6. Voluntary enhanced cocontraction of hamstring muscles during open kinetic chain leg extension exercise: its potential unloading effect on the anterior cruciate ligament.

    Science.gov (United States)

    Biscarini, Andrea; Benvenuti, Paolo; Botti, Fabio M; Brunetti, Antonella; Brunetti, Orazio; Pettorossi, Vito E

    2014-09-01

    A number of research studies provide evidence that hamstring cocontraction during open kinetic chain knee extension exercises enhances tibiofemoral (TF) stability and reduces the strain on the anterior cruciate ligament. To determine the possible increase in hamstring muscle coactivation caused by a voluntary cocontraction effort during open kinetic chain leg-extension exercises, and to assess whether an intentional hamstring cocontraction can completely suppress the anterior TF shear force during these exercises. Descriptive laboratory study. Knee kinematics as well as electromyographic activity in the semitendinosus (ST), semimembranosus (SM), biceps femoris (BF), and quadriceps femoris muscles were measured in 20 healthy men during isotonic leg extension exercises with resistance (R) ranging from 10% to 80% of the 1-repetition maximum (1RM). The same exercises were also performed while the participants attempted to enhance hamstring coactivation through a voluntary cocontraction effort. The data served as input parameters for a model to calculate the shear and compressive TF forces in leg extension exercises for any set of coactivation patterns of the different hamstring muscles. For R≤ 40% 1RM, the peak coactivation levels obtained with intentional cocontraction (l) were significantly higher (P hamstring muscle, maximum level l was reached at R = 30% 1RM, corresponding to 9.2%, 10.5%, and 24.5% maximum voluntary isometric contraction (MVIC) for the BF, ST, and SM, respectively, whereas the ratio l/l 0 reached its maximum at R = 20% 1RM and was approximately 2, 3, and 4 for the BF, SM, and ST, respectively. The voluntary enhanced coactivation level l obtained for R≤ 30% 1RM completely suppressed the anterior TF shear force developed by the quadriceps during the exercise. In leg extension exercises with resistance R≤ 40% 1RM, coactivation of the BF, SM, and ST can be significantly enhanced (up to 2, 3, and 4 times, respectively) by a voluntary hamstring

  7. Comparative Label-Free Mass Spectrometric Analysis of Mildly versus Severely Affected mdx Mouse Skeletal Muscles Identifies Annexin, Lamin, and Vimentin as Universal Dystrophic Markers

    Directory of Open Access Journals (Sweden)

    Ashling Holland

    2015-06-01

    Full Text Available The primary deficiency in the membrane cytoskeletal protein dystrophin results in complex changes in dystrophic muscles. In order to compare the degree of secondary alterations in differently affected subtypes of skeletal muscles, we have conducted a global analysis of proteome-wide changes in various dystrophin-deficient muscles. In contrast to the highly degenerative mdx diaphragm muscle, which showed considerable alterations in 35 distinct proteins, the spectrum of mildly to moderately dystrophic skeletal muscles, including interosseus, flexor digitorum brevis, soleus, and extensor digitorum longus muscle, exhibited a smaller number of changed proteins. Compensatory mechanisms and/or cellular variances may be responsible for differing secondary changes in individual mdx muscles. Label-free mass spectrometry established altered expression levels for diaphragm proteins associated with contraction, energy metabolism, the cytoskeleton, the extracellular matrix and the cellular stress response. Comparative immunoblotting verified the differences in the degree of secondary changes in dystrophin-deficient muscles and showed that the up-regulation of molecular chaperones, the compensatory increase in proteins of the intermediate filaments, the fibrosis-related increase in collagen levels and the pathophysiological decrease in calcium binding proteins is more pronounced in mdx diaphragm as compared to the less severely affected mdx leg muscles. Annexin, lamin, and vimentin were identified as universal dystrophic markers.

  8. Comparative Label-Free Mass Spectrometric Analysis of Mildly versus Severely Affected mdx Mouse Skeletal Muscles Identifies Annexin, Lamin, and Vimentin as Universal Dystrophic Markers.

    Science.gov (United States)

    Holland, Ashling; Henry, Michael; Meleady, Paula; Winkler, Claudia K; Krautwald, Mirjam; Brinkmeier, Heinrich; Ohlendieck, Kay

    2015-06-19

    The primary deficiency in the membrane cytoskeletal protein dystrophin results in complex changes in dystrophic muscles. In order to compare the degree of secondary alterations in differently affected subtypes of skeletal muscles, we have conducted a global analysis of proteome-wide changes in various dystrophin-deficient muscles. In contrast to the highly degenerative mdx diaphragm muscle, which showed considerable alterations in 35 distinct proteins, the spectrum of mildly to moderately dystrophic skeletal muscles, including interosseus, flexor digitorum brevis, soleus, and extensor digitorum longus muscle, exhibited a smaller number of changed proteins. Compensatory mechanisms and/or cellular variances may be responsible for differing secondary changes in individual mdx muscles. Label-free mass spectrometry established altered expression levels for diaphragm proteins associated with contraction, energy metabolism, the cytoskeleton, the extracellular matrix and the cellular stress response. Comparative immunoblotting verified the differences in the degree of secondary changes in dystrophin-deficient muscles and showed that the up-regulation of molecular chaperones, the compensatory increase in proteins of the intermediate filaments, the fibrosis-related increase in collagen levels and the pathophysiological decrease in calcium binding proteins is more pronounced in mdx diaphragm as compared to the less severely affected mdx leg muscles. Annexin, lamin, and vimentin were identified as universal dystrophic markers.

  9. The effect Mat Pilates practice on muscle mass in elderly women

    Directory of Open Access Journals (Sweden)

    Leliz Cristina Sampaio Queiroz

    2016-01-01

    Full Text Available Objective: to verify that the Mat Pilates practice increases muscle mass in elderly women. Methods: quasi-experimental study with primary data collection and with a convenience sample. The muscle mass of 43 elderly was evaluated for 11 weeks, by calculating the arm muscle area, before and after the intervention. Results:statistically significant difference was observed (p<0.002 between the average value of the arm muscle area, before (35.56cm2 and after the exercises (42.72cm2. Conclusion: mat Pilates program generates positive effect on increasing the muscle mass of elderly.

  10. Correlation between Body Mass Index, Gender, and Skeletal Muscle Mass Cut off Point in Bandung

    Directory of Open Access Journals (Sweden)

    Richi Hendrik Wattimena

    2017-09-01

    Full Text Available Objective: To determine the average skeletal muscle mass (SMM value in young adults as a reference population; to analyze the correlation of gender, and body mass index to the cut off point; and to determine skeletal muscle mass cut off points of population in Bandung, Indonesia. Methods: This was a cross-sectional study involving 199 participants, 122 females and 77 males. The sampling technique used was the multistage random sampling. The participants were those who lived in four major regions in Bandung, Indonesia: Sukajadi, Cicadas, Buah Batu, and Cibaduyut. Results: The average appendicular skeletal mass index (ASMI in females and males based on body mass index (BMI were identified. The average ASMI values for normal BMI in females was 5.982±0.462 kg/m2 while the average ASMI values normal BMI for males was 7.581±0.744 kg/m2 Conclusions: A correlation between BMI and ASMI that was considered statistically significant was found in females (0.7712; p<0.05 and a very significant correlation was seen in males (0.870; p<0.05. The cut off points were defined by the normal BMI, which were 5.059 for females and 6.093 for males.

  11. Differential control of muscle mass in type 1 and type 2 diabetes mellitus.

    Science.gov (United States)

    Sala, David; Zorzano, Antonio

    2015-10-01

    Diabetes mellitus--whether driven by insulin deficiency or insulin resistance--causes major alterations in muscle metabolism. These alterations have an impact on nutrient handling, including the metabolism of glucose, lipids, and amino acids, and also on muscle mass and strength. However, the ways in which the distinct forms of diabetes affect muscle mass differ greatly. The most common forms of diabetes mellitus are type 1 and type 2. Thus, whereas type 1 diabetic subjects without insulin treatment display a dramatic loss of muscle, most type 2 diabetic subjects show no changes or even an increase in muscle mass. However, the most commonly used rodent models of type 2 diabetes are characterized by muscle atrophy and do not mimic the features of the disease in humans in terms of muscle mass. In this review, we analyze the processes that are differentially regulated under these forms of diabetes and propose regulatory mechanisms to explain them.

  12. Norepinephrine spillover from skeletal muscle during exercise in humans

    DEFF Research Database (Denmark)

    Savard, G K; Richter, Erik; Strange, S

    1989-01-01

    -legged knee extension either alone or in combination with the knee extensors of the other leg and/or with the arms. The range of work intensities varied between 24 and 71% (mean) of subjects' maximal aerobic capacity (% VO2max). Leg blood flow, measured in the femoral vein by thermodilution, was determined...... legs, with a steeper rise occurring approximately 70% VO2max. These increases were not associated with any significant changes in leg blood flow or leg vascular conductance at the exercise intensities examined. These results suggest that, as the total active muscle mass increases, the rise...

  13. Effects of fatigue on lower limb, pelvis and trunk kinematics and lower limb muscle activity during single-leg landing after anterior cruciate ligament reconstruction.

    Science.gov (United States)

    Lessi, Giovanna Camparis; Serrão, Fábio Viadanna

    2017-08-01

    Because there are no studies that have evaluated the effects of fatigue on the kinematics of the trunk and pelvis or on muscle activation in subjects with ACL reconstruction, the aim of this study was to evaluate the effects of fatigue on the lower limb, pelvis and trunk kinematics and lower limb muscle activation in subjects with ACL reconstruction during a single-leg landing compared to a healthy control group. The participants included 20 subjects with ACL reconstruction (ACL reconstruction group-ACLRG) and 20 healthy subjects (control group-CG) who were aged between 18 and 35 years. Kinematic and electromyographic analyses were performed during a single-leg landing before and after fatigue. The fatigue protocol included a series of 10 squats, two vertical jumps, and 20 steps. The effects of fatigue were increased peak trunk flexion and increased activation of the vastus lateralis, biceps femoris (BF) and gluteus maximus (GMax) during the landing phase. After the fatigue protocol, an increase in peak trunk flexion and activation of the GMax and BF were observed, most likely as a strategy to reduce the load on the ACL. ACL injury prevention programs should include strength and endurance exercises for the hip and trunk extensor muscles so that they can efficiently control trunk flexion during landing. Prospective comparative study, Level II.

  14. Performance, carcass yield, and qualitative characteristics of breast and leg muscles of broilers fed diets supplemented with vitamin E at different ages

    Directory of Open Access Journals (Sweden)

    FR Leonel

    2007-06-01

    Full Text Available The effects of vitamin E supplementation (300 mg/kg diet in the diet of broiler chickens for different periods during rearing on the performance and qualitative traits of breast and leg muscles were evaluated. Seven hundred and twenty day-old chicks were distributed into six treatments: basal diet (25 mg vitamin E/kg diet, and diet supplemented with vitamin E from 1 to 15, 1 to 30, 1 to 45, 14 to 45 and 30 to 45 days of age. Vitamin E content, lipid percentage, TBARS (0 and 3 days of storage, color (*L, *a, *b, and pH were evaluated. There were no differences (p>0.05 among treatments in performance, carcass yield, and cut yields. Qualitative parameters (pH and color presented no differences, although vitamin E positively affected TBARS values at 3 days of storage, mainly in leg muscles. Vitamin E levels in both muscles were higher in the birds supplemented throughout the experiment.

  15. Supplemental protein in support of muscle mass and health: advantage whey.

    Science.gov (United States)

    Devries, Michaela C; Phillips, Stuart M

    2015-03-01

    Skeletal muscle is an integral body tissue playing key roles in strength, performance, physical function, and metabolic regulation. It is essential for athletes to ensure that they have optimal amounts of muscle mass to ensure peak performance in their given sport. However, the role of maintaining muscle mass during weight loss and as we age is an emerging concept, having implications in chronic disease prevention, functional capacity, and quality of life. Higher-protein diets have been shown to: (1) promote gains in muscle mass, especially when paired with resistance training; (2) spare muscle mass loss during caloric restriction; and (3) attenuate the natural loss of muscle mass that accompanies aging. Protein quality is important to the gain and maintenance of muscle mass. Protein quality is a function of protein digestibility, amino acid content, and the resulting amino acid availability to support metabolic function. Whey protein is one of the highest-quality proteins given its amino acid content (high essential, branched-chain, and leucine amino acid content) and rapid digestibility. Consumption of whey protein has a robust ability to stimulate muscle protein synthesis. In fact, whey protein has been found to stimulate muscle protein synthesis to a greater degree than other proteins such as casein and soy. This review examines the existing data supporting the role for protein consumption, with an emphasis on whey protein, in the regulation of muscle mass and body composition in response to resistance training, caloric restriction, and aging. © 2015 Institute of Food Technologists®

  16. A New Equation to Estimate Muscle Mass from Creatinine and Cystatin C.

    Directory of Open Access Journals (Sweden)

    Sun-wook Kim

    Full Text Available With evaluation for physical performance, measuring muscle mass is an important step in detecting sarcopenia. However, there are no methods to estimate muscle mass from blood sampling.To develop a new equation to estimate total-body muscle mass with serum creatinine and cystatin C level, we designed a cross-sectional study with separate derivation and validation cohorts. Total body muscle mass and fat mass were measured using dual-energy x-ray absorptiometry (DXA in 214 adults aged 25 to 84 years who underwent physical checkups from 2010 to 2013 in a single tertiary hospital. Serum creatinine and cystatin C levels were also examined.Serum creatinine was correlated with muscle mass (P < .001, and serum cystatin C was correlated with body fat mass (P < .001 after adjusting glomerular filtration rate (GFR. After eliminating GFR, an equation to estimate total-body muscle mass was generated and coefficients were calculated in the derivation cohort. There was an agreement between muscle mass calculated by the novel equation and measured by DXA in both the derivation and validation cohort (P < .001, adjusted R2 = 0.829, β = 0.95, P < .001, adjusted R2 = 0.856, β = 1.03, respectively.The new equation based on serum creatinine and cystatin C levels can be used to estimate total-body muscle mass.

  17. Leg and arm lactate and substrate kinetics during exercise

    DEFF Research Database (Denmark)

    Van Hall, Gerrit; Jensen-Urstad, M; Rosdahl, H

    2003-01-01

    To study the role of muscle mass and muscle activity on lactate and energy kinetics during exercise, whole body and limb lactate, glucose, and fatty acid fluxes were determined in six elite cross-country skiers during roller-skiing for 40 min with the diagonal stride (Continuous Arm + Leg) followed...... by 10 min of double poling and diagonal stride at 72-76% maximal O(2) uptake. A high lactate appearance rate (R(a), 184 +/- 17 micromol x kg(-1) x min(-1)) but a low arterial lactate concentration ( approximately 2.5 mmol/l) were observed during Continuous Arm + Leg despite a substantial net lactate...... release by the arm of approximately 2.1 mmol/min, which was balanced by a similar net lactate uptake by the leg. Whole body and limb lactate oxidation during Continuous Arm + Leg was approximately 45% at rest and approximately 95% of disappearance rate and limb lactate uptake, respectively. Limb lactate...

  18. Relationships of 35 lower limb muscles to height and body mass quantified using MRI.

    Science.gov (United States)

    Handsfield, Geoffrey G; Meyer, Craig H; Hart, Joseph M; Abel, Mark F; Blemker, Silvia S

    2014-02-07

    Skeletal muscle is the most abundant tissue in the body and serves various physiological functions including the generation of movement and support. Whole body motor function requires adequate quantity, geometry, and distribution of muscle. This raises the question: how do muscles scale with subject size in order to achieve similar function across humans? While much of the current knowledge of human muscle architecture is based on cadaver dissection, modern medical imaging avoids limitations of old age, poor health, and limited subject pool, allowing for muscle architecture data to be obtained in vivo from healthy subjects ranging in size. The purpose of this study was to use novel fast-acquisition MRI to quantify volumes and lengths of 35 major lower limb muscles in 24 young, healthy subjects and to determine if muscle size correlates with bone geometry and subject parameters of mass and height. It was found that total lower limb muscle volume scales with mass (R(2)=0.85) and with the height-mass product (R(2)=0.92). Furthermore, individual muscle volumes scale with total muscle volume (median R(2)=0.66), with the height-mass product (median R(2)=0.61), and with mass (median R(2)=0.52). Muscle volume scales with bone volume (R(2)=0.75), and muscle length relative to bone length is conserved (median s.d.=2.1% of limb length). These relationships allow for an arbitrary subject's individual muscle volumes to be estimated from mass or mass and height while muscle lengths may be estimated from limb length. The dataset presented here can further be used as a normative standard to compare populations with musculoskeletal pathologies. © 2013 Published by Elsevier Ltd.

  19. Avian pectoral muscle size rapidly tracks body mass changes during flight, fasting and fuelling.

    Science.gov (United States)

    Lindström, A; Kvist, A; Piersma, T; Dekinga, A; Dietz, M W

    2000-03-01

    We used ultrasonic imaging to monitor short-term changes in the pectoral muscle size of captive red knots Calidris canutus. Pectoral muscle thickness changed rapidly and consistently in parallel with body mass changes caused by flight, fasting and fuelling. Four knots flew repeatedly for 10 h periods in a wind tunnel. Over this period, pectoral muscle thickness decreased in parallel with the decrease in body mass. The change in pectoral muscle thickness during flight was indistinguishable from that during periods of natural and experimental fasting and fuelling. The body-mass-related variation in pectoral muscle thickness between and within individuals was not related to the amount of flight, indicating that changes in avian muscle do not require power-training as in mammals. Our study suggests that it is possible for birds to consume and replace their flight muscles on a time scale short enough to allow these muscles to be used as part of the energy supply for migratory flight. The adaptive significance of the changes in pectoral muscle mass cannot be explained by reproductive needs since our knots were in the early winter phase of their annual cycle. Instead, pectoral muscle mass changes may reflect (i) the breakdown of protein during heavy exercise and its subsequent restoration, (ii) the regulation of flight capacity to maintain optimal flight performance when body mass varies, or (iii) the need for a particular protein:fat ratio in winter survival stores.

  20. The intriguing regulators of muscle mass in sarcopenia and muscular dystrophy

    Directory of Open Access Journals (Sweden)

    Kunihiro eSakuma

    2014-08-01

    Full Text Available Recent advances in our understanding of the biology of muscle have led to new interest in the pharmacological treatment of muscle wasting. Loss of muscle mass and increased intramuscular fibrosis occur in both sarcopenia and muscular dystrophy. Several regulators (mTOR, serum response factor, atrogin-1, myostatin, etc seem to modulate protein synthesis and degradation or transcription of muscle-specific genes during both sarcopenia and muscular dystrophy. This review provides an overview of the adaptive changes in several regulators of muscle mass in both sarcopenia and muscular dystrophy.

  1. The influence of foot arch on ankle joint torques andon sEMG signal amplitude in selected lower leg muscles

    Directory of Open Access Journals (Sweden)

    Żebrowska Kinga

    2016-09-01

    Full Text Available Introduction: This study sought to assess the influence of proper foot arch on electromyographic activity of selected lower limb muscles. The aim of this work was to evaluate the effects of foot arch on the activity of selected muscles and to determine whether electromyography might help to identify types of flat feet resulting from muscle- or ligament-related causes.

  2. Creatine Supplementation and Skeletal Muscle Metabolism for Building Muscle Mass- Review of the Potential Mechanisms of Action.

    Science.gov (United States)

    Farshidfar, Farnaz; Pinder, Mark A; Myrie, Semone B

    2017-01-01

    Creatine, a very popular supplement among athletic populations, is of growing interest for clinical applications. Since over 90% of creatine is stored in skeletal muscle, the effect of creatine supplementation on muscle metabolism is a widely studied area. While numerous studies over the past few decades have shown that creatine supplementation has many favorable effects on skeletal muscle physiology and metabolism, including enhancing muscle mass (growth/hypertrophy); the underlying mechanisms are poorly understood. This report reviews studies addressing the mechanisms of action of creatine supplementation on skeletal muscle growth/hypertrophy. Early research proposed that the osmotic effect of creatine supplementation serves as a cellular stressor (osmosensing) that acts as an anabolic stimulus for protein synthesis signal pathways. Other reports indicated that creatine directly affects muscle protein synthesis via modulations of components in the mammalian target of rapamycin (mTOR) pathway. Creatine may also directly affect the myogenic process (formation of muscle tissue), by altering secretions of myokines, such as myostatin and insulin-like growth factor-1, and expressions of myogenic regulatory factors, resulting in enhanced satellite cells mitotic activities and differentiation into myofiber. Overall, there is still no clear understanding of the mechanisms of action regarding how creatine affects muscle mass/growth, but current evidence suggests it may exert its effects through multiple approaches, with converging impacts on protein synthesis and myogenesis. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  3. Leg Strength and Lean Mass Symmetry Influences Kicking Performance in Australian Football

    OpenAIRE

    Hart, Nicolas H.; Nimphius, Sophia; Spiteri, Tania; Newton, Robert U.

    2014-01-01

    Differential loading patterns during game-based participation may produce or exacerbate strength imbalances between the lower limbs. It is currently unknown whether such imbalances are functionally beneficial or detrimental to performance. This study assessed the influence of lower limb strength and lean mass symmetry on kicking accuracy in Australian Football. Thirty-one Australian footballers were required to perform a kicking assessment, producing ten drop punt kicks over twenty metres to ...

  4. Does Skeletal Muscle Mass Influence Breast Cancer? Evaluating Mammary Tumorigenesis and Progression Genetically Hyper-Muscular Mice

    National Research Council Canada - National Science Library

    Zimmers, Teresa

    2006-01-01

    .... Mice lacking the skeletal muscle-specific muscle growth inhibitor myostatin and mice expressing a dominant negative form of the myostatin receptor, Activin Receptor Type IIB, display heightened muscle mass...

  5. The effect of lumbar posture on abdominal muscle thickness during an isometric leg task in people with and without non-specific low back pain.

    Science.gov (United States)

    Pinto, Rafael Zambelli; Ferreira, Paulo Henrique; Franco, Marcia Rodrigues; Ferreira, Mariana Calais; Ferreira, Manuela Loureiro; Teixeira-Salmela, Luci Fuscaldi; Oliveira, Vinicius C; Maher, Christopher

    2011-12-01

    This study investigated the effect of lumbar posture on function of transversus abdominis (TrA) and obliquus internus (OI) in people with and without non-specific low back pain (LBP) during a lower limb task. Rehabilitative ultrasound was used to measure thickness change of TrA and OI during a lower limb task that challenged the stability of the spine. Measures were taken in supine in neutral and flexed lumbar postures in 30 patients and 30 healthy subjects. Data were analysed using a two-way (groups, postures) ANOVA. Our results showed that lumbar posture influenced percent thickness change of the TRA muscle but not for OI. An interaction between group and posture was found for TrA thickness change (F(1,56) = 6.818, p = 0.012). For this muscle, only healthy participants showed greater thickness change with neutral posture compared to flexed (mean difference = 6.2%; 95% CI: 3.1-9.3%; p posture can facilitate an increase in thickness of the TrA muscle while performing a leg task, however this effect was not observed for this muscle in patients with LBP. No significant difference in TrA and OI thickness change between people with and without non-specific LBP was found. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. Associations of Muscle Mass and Strength with All-Cause Mortality among US Older Adults.

    Science.gov (United States)

    Li, Ran; Xia, Jin; Zhang, X I; Gathirua-Mwangi, Wambui Grace; Guo, Jianjun; Li, Yufeng; McKenzie, Steve; Song, Yiqing

    2018-03-01

    Recent studies suggested that muscle mass and muscle strength may independently or synergistically affect aging-related health outcomes in older adults; however, prospective data on mortality in the general population are sparse. We aimed to prospectively examine individual and joint associations of low muscle mass and low muscle strength with all-cause mortality in a nationally representative sample. This study included 4449 participants age 50 yr and older from the National Health and Nutrition Examination Survey 1999 to 2002 with public use 2011 linked mortality files. Weighted multivariable logistic regression models were adjusted for age, sex, race, body mass index (BMI), smoking, alcohol use, education, leisure time physical activity, sedentary time, and comorbid diseases. Overall, the prevalence of low muscle mass was 23.1% defined by appendicular lean mass (ALM) and 17.0% defined by ALM/BMI, and the prevalence of low muscle strength was 19.4%. In the joint analyses, all-cause mortality was significantly higher among individuals with low muscle strength, whether they had low muscle mass (odds ratio [OR], 2.03; 95% confidence interval [CI], 1.27-3.24 for ALM; OR, 2.53; 95% CI, 1.64-3.88 for ALM/BMI) or not (OR, 2.66; 95% CI, 1.53-4.62 for ALM; OR, 2.17; 95% CI, 1.29-3.64 for ALM/BMI). In addition, the significant associations between low muscle strength and all-cause mortality persisted across different levels of metabolic syndrome, sedentary time, and LTPA. Low muscle strength was independently associated with elevated risk of all-cause mortality, regardless of muscle mass, metabolic syndrome, sedentary time, or LTPA among US older adults, indicating the importance of muscle strength in predicting aging-related health outcomes in older adults.

  7. Is dynamometry able to infer the risk of muscle mass loss in patients with COPD?

    Science.gov (United States)

    Ramos, Dionei; Bertolini, Giovana Navarro; Leite, Marceli Rocha; Carvalho Junior, Luiz Carlos Soares; da Silva Pestana, Paula Roberta; dos Santos, Vanessa Ribeiro; Fortaleza, Ana Claudia de Souza; Rodrigues, Fernanda Maria Machado; Ramos, Ercy Mara Cipulo

    2015-01-01

    Sarcopenia is characterized by a progressive and generalized decrease of strength and muscle mass. Muscle mass loss is prevalent in patients with chronic obstructive pulmonary disease (COPD) as a result of both the disease and aging. Some methods have been proposed to assess body composition (and therefore identify muscle mass loss) in this population. Despite the high accuracy of some methods, they require sophisticated and costly equipment. The purpose of this study was to infer the occurrence of muscle mass loss measured by a sophisticated method (dual energy X-ray absorptiometry [DEXA]) using a more simple and affordable equipment (dynamometer). Fifty-seven stable subjects with COPD were evaluated for anthropometric characteristics, lung function, functional exercise capacity, body composition, and peripheral muscle strength. A binary logistic regression model verified whether knee-extension strength (measured by dynamometry) could infer muscle mass loss (from DEXA). Patients with decreased knee-extension strength were 5.93 times more likely to have muscle mass loss, regardless of sex, disease stage, and functional exercise capacity (P=0.045). Knee-extension dynamometry was able to infer muscle mass loss in patients with COPD.

  8. Volitional Weight-Lifting in Rats Promotes Adaptation via Performance and Muscle Morphology prior to Gains in Muscle Mass

    Directory of Open Access Journals (Sweden)

    Erik P. Rader

    2014-01-01

    Full Text Available Investigation of volitional animal models of resistance training has been instrumental in our understanding of adaptive training. However, these studies have lacked reactive force measurements, a precise performance measure, and morphological analysis at a distinct phase of training - when initial strength gains precede muscle hypertrophy. Our aim was to expose rats to one month of training (70 or 700 g load on a custom-designed weight-lifting apparatus for analysis of reactive forces and muscle morphology prior to muscle hypertrophy. Exclusively following 700 g load training, forces increased by 21% whereas muscle masses remained unaltered. For soleus (SOL and tibialis anterior (TA muscles, 700 g load training increased muscle fiber number per unit area by ~20% and decreased muscle fiber area by ~20%. Additionally, number of muscle fibers per section increased by 18% for SOL muscles. These results establish that distinct morphological alterations accompany early strength gains in a volitional animal model of load-dependent adaptive resistance training.

  9. Diffusion Properties and 3D Architecture of Human Lower Leg Muscles Assessed with Ultra-High-Field-Strength Diffusion-Tensor MR Imaging and Tractography: Reproducibility and Sensitivity to Sex Difference and Intramuscular Variability.

    Science.gov (United States)

    Fouré, Alexandre; Ogier, Augustin C; Le Troter, Arnaud; Vilmen, Christophe; Feiweier, Thorsten; Guye, Maxime; Gondin, Julien; Besson, Pierre; Bendahan, David

    2018-05-01

    Purpose To demonstrate the reproducibility of the diffusion properties and three-dimensional structural organization measurements of the lower leg muscles by using diffusion-tensor imaging (DTI) assessed with ultra-high-field-strength (7.0-T) magnetic resonance (MR) imaging and tractography of skeletal muscle fibers. On the basis of robust statistical mapping analyses, this study also aimed at determining the sensitivity of the measurements to sex difference and intramuscular variability. Materials and Methods All examinations were performed with ethical review board approval; written informed consent was obtained from all volunteers. Reproducibility of diffusion tensor indexes assessment including eigenvalues, mean diffusivity, and fractional anisotropy (FA) as well as muscle volume and architecture (ie, fiber length and pennation angle) were characterized in lower leg muscles (n = 8). Intramuscular variability and sex differences were characterized in young healthy men and women (n = 10 in each group). Student t test, statistical parametric mapping, correlation coefficients (Spearman rho and Pearson product-moment) and coefficient of variation (CV) were used for statistical data analysis. Results High reproducibility of measurements (mean CV ± standard deviation, 4.6% ± 3.8) was determined in diffusion properties and architectural parameters. Significant sex differences were detected in FA (4.2% in women for the entire lower leg; P = .001) and muscle volume (21.7% in men for the entire lower leg; P = .008), whereas architecture parameters were almost identical across sex. Additional differences were found independently of sex in diffusion properties and architecture along several muscles of the lower leg. Conclusion The high-spatial-resolution DTI assessed with 7.0-T MR imaging allows a reproducible assessment of structural organization of superficial and deep muscles, giving indirect information on muscle function. © RSNA, 2018 Online supplemental material is

  10. Effects of 8 weeks of Xpand® 2X pre workout supplementation on skeletal muscle hypertrophy, lean body mass, and strength in resistance trained males.

    Science.gov (United States)

    Lowery, Ryan P; Joy, Jordan M; Dudeck, Joshua E; Oliveira de Souza, Eduardo; McCleary, Sean A; Wells, Shawn; Wildman, Robert; Wilson, Jacob M

    2013-10-09

    Xpand® 2X is a proprietary blend comprised of branched chain amino acids, creatine monohydrate, beta-alanine (CarnoSyn®), quercetin, coenzymated B-vitamins, alanyl-glutamine (Sustamine®), and natural nitrate sources from pomegranate and beet root extracts purported to enhance the neuromuscular adaptations of resistance training. However to date, no long-term studies have been conducted with this supplement. The purpose of this study was to investigate the effects of a multi-ingredient performance supplement (MIPS) on skeletal muscle hypertrophy, lean body mass and lower body strength in resistance-trained males. Twenty resistance-trained males (21.3 ± 1.9 years) were randomly assigned to consume a MIPS or a placebo of equal weight and volume (food-grade orange flavors and sweeteners) in a double-blind manner, 30 minutes prior to exercise. All subjects participated in an 8-week, 3-day per week, periodized, resistance-training program that was split-focused on multi-joint movements such as leg press, bench press, and bent-over rows. Ultrasonography measured muscle thickness of the quadriceps, dual-energy X-ray absorptiometry (DEXA) determined lean body mass, and strength of the bench press and leg press were determined at weeks 0, 4, and 8 of the study. Data were analyzed with a 2 × 3 repeated measures ANOVA with LSD post hoc tests utilized to locate differences. There was a significant group-by-time interaction in which the MIPS supplementation resulted in a significant (p supplementation nor the placebo in leg press strength (p = .08). MIPS supplementation also resulted in a significant increase in lean body mass (7.8% vs. 3.6%) and quadriceps muscle thickness (11.8% vs. 4.5%) compared with placebo (group*time, p hypertrophy in resistance-trained men.

  11. [More muscle mass in men: explanatory model for superior outcome after total hip arthroplasty].

    Science.gov (United States)

    Preininger, B; Schmorl, K; von Roth, P; Winkler, T; Matziolis, G; Perka, C; Tohtz, S

    2013-02-01

    Men show better functional results after total hip arthroplasty (THA). The aim of this study was a patient-specific analysis of the hip joint muscles in comparison to the joint geometry. In this study 93 computed tomography (CT) scans of the pelvis (45 men, 48 women) were analyzed to determine hip joint geometry and the volume of the gluteus medius (GMV), gluteus maximus (GXV) and tensor fasciae latae (TFL) muscles. The abduction muscle volumes were analyzed with respect to patient-specific adduction moments. The absolute total volume of the hip muscular system (TMV) was larger in men than in women (1913 ccm vs. 1479 ccm; p abduction muscle mass in order to balance adduction moments occurring in the hip joint and therefore have more muscle mass to compensate the inevitable intraoperative muscle damage during THA. This argument supports the extraordinary importance of muscle sparing surgical techniques in women.

  12. Assessment of muscle mass relative to fat mass and associations with physical functioning in rheumatoid arthritis.

    Science.gov (United States)

    Baker, Joshua F; Giles, Jon T; Weber, David; Leonard, Mary B; Zemel, Babette S; Long, Jin; Ibrahim, Said; Katz, Patricia P

    2017-06-01

    To determine whether a novel measure of appendicular lean mass relative to fat mass is associated with physical functioning in RA. In a cross-sectional design, three independent RA cohorts were retrospectively analysed. Whole-body DXA measures of appendicular lean mass index (ALMI, kg/m 2 ) and fat mass index (FMI, kg/m 2 ) were converted to age, sex and race-specific Z-scores using published National Health and Nutrition Examination Survey reference ranges. Adiposity-adjusted ALMI Z-scores (ALMI FMI ) were determined using a published method to adjust for normal associations between ALMI and FMI Z-scores. Associations between ALMI Z-scores, ALMI FMI Z-scores and physical functioning were assessed after adjusting for age, sex and study. Functional outcomes assessed included the HAQ, Valued Life Activities assessment and Short Physical Performance Battery. Low lean for age was defined as a Z-score of -1 or less. Our sample consisted of 442 patients with RA. The combined cohort had a mean ALMI Z-score of - 0.51 (1.08) and a mean ALMI FMI Z-score of - 0.58 (1.53), suggesting muscle mass deficits compared with a nationally representative sample. Greater ALMI FMI Z-scores demonstrated stronger associations with better functional outcomes compared with ALMI Z-scores. Associations were not attenuated with adjustment for systemic inflammation or pain. The FMI Z-score was independently associated with physical functioning, with a stronger association seen among patients with greater FMI Z-score. Adiposity-adjusted definitions of low lean mass more clearly identified those with functional impairment. Estimates of appendicular lean mass that are adjusted for adiposity demonstrate stronger positive associations with functional outcomes compared with unadjusted estimates. © The Author 2017. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oup.com

  13. mTOR as a Key Regulator in Maintaining Skeletal Muscle Mass

    Directory of Open Access Journals (Sweden)

    Mee-Sup Yoon

    2017-10-01

    Full Text Available Maintenance of skeletal muscle mass is regulated by the balance between anabolic and catabolic processes. Mammalian target of rapamycin (mTOR is an evolutionarily conserved serine/threonine kinase, and is known to play vital roles in protein synthesis. Recent findings have continued to refine our understanding of the function of mTOR in maintaining skeletal muscle mass. mTOR controls the anabolic and catabolic signaling of skeletal muscle mass, resulting in the modulation of muscle hypertrophy and muscle wastage. This review will highlight the fundamental role of mTOR in skeletal muscle growth by summarizing the phenotype of skeletal-specific mTOR deficiency. In addition, the evidence that mTOR is a dual regulator of anabolism and catabolism in skeletal muscle mass will be discussed. A full understanding of mTOR signaling in the maintenance of skeletal muscle mass could help to develop mTOR-targeted therapeutics to prevent muscle wasting.

  14. Alternate Mediterranean diet score is positively associated with skeletal muscle mass index in middle-aged adults.

    Science.gov (United States)

    Tian, Hui-Yuan; Qiu, Rui; Jing, Li-Peng; Chen, Zhan-Yong; Chen, Geng-Dong; Chen, Yu-Ming

    2017-04-01

    Researches have suggested Mediterranean diet might lower the risk of chronic diseases, but data on skeletal muscle mass (SMM) are limited. This community-based cross-sectional study examined the association between the alternate Mediterranean diet score (aMDS) and SMM in 2230 females and 1059 males aged 40-75 years in Guangzhou, China. General information and habitual dietary information were assessed in face-to-face interviews conducted during 2008-2010 and 3 years later. The aMDS was calculated by summing the dichotomous points for the items of higher intakes of whole grain, vegetables, fruits, legumes, nuts, fish and ratio of MUFA:SFA, lower red meat and moderate ethanol consumption. The SMM of the whole body, limbs, arms and legs were measured using dual-energy X-ray absorptiometry during 2011-2013. After adjusting for potential covariates, higher aMDS was positively associated with skeletal muscle mass index (SMI, SMM/height2, kg/m2) at all of the studied sites in males (all P trend0·05). Age-stratified analyses showed that the favourable associations tended to be more pronounced in the younger subjects aged less than the medians of 59·2 and 62·2 years in females and males (P interaction>0·10). In conclusion, the aMDS shows protective associations with SMM in Chinese adults, particularly in male and younger subjects.

  15. High risk of malnutrition is associated with low muscle mass in older hospitalized patients - a prospective cohort study.

    Science.gov (United States)

    Pierik, Vincent D; Meskers, Carel G M; Van Ancum, Jeanine M; Numans, Siger T; Verlaan, Sjors; Scheerman, Kira; Kruizinga, Roeliene C; Maier, Andrea B

    2017-06-05

    Malnutrition, low muscle strength and muscle mass are highly prevalent in older hospitalized patients and associated with adverse outcomes. Malnutrition may be a risk factor for developing low muscle mass. We aimed to investigate the association between the risk of malnutrition and 1) muscle strength and muscle mass at admission and 2) the change of muscle strength and muscle mass during hospitalization in older patients. The EMPOWER study included 378 patients aged seventy years or older who were acutely or electively admitted to four different wards of an academic teaching hospital in Amsterdam. Patients were grouped into low risk of malnutrition and high risk of malnutrition based on the Short Nutritional Assessment Questionnaire (SNAQ) score and were assessed for hand grip strength and muscle mass using hand held dynamometry respectively bioelectrical impedance analysis (BIA) within 48 h after admission and at day seven, or earlier at the day of discharge. Muscle mass was expressed as skeletal muscle mass, appendicular lean mass, fat free mass and the skeletal muscle index. The mean age of the patients was 79.7 years (SD 6.39), 48.9% were female. At admission, being at high risk of malnutrition was significantly associated with lower muscle mass (Odds Ratio, 95% CI, 0.90, 0.85-0.96), but not with muscle strength. Muscle strength and muscle mass did not change significantly during hospitalization in both groups. In older hospitalized patients, a high risk of malnutrition is associated with lower muscle mass at admission, but not with muscle strength nor with change of either muscle strength or muscle mass during hospitalization.

  16. Single leg stance control in individuals with symptomatic gluteal tendinopathy.

    Science.gov (United States)

    Allison, Kim; Bennell, Kim L; Grimaldi, Alison; Vicenzino, Bill; Wrigley, Tim V; Hodges, Paul W

    2016-09-01

    Lateral hip pain during single leg loading, and hip abductor muscle weakness, are associated with gluteal tendinopathy, but it has not been shown how or whether kinematics in single leg stance differ in those with gluteal tendinopathy. To compare kinematics in preparation for, and during, single leg stance between individuals with and without gluteal tendinopathy, and the effect of hip abductor muscle strength on kinematics. Twenty individuals with gluteal tendinopathy and 20 age-matched pain-free controls underwent three-dimensional kinematic analysis of single leg stance and maximum isometric hip abductor strength testing. Maximum values of hip adduction, pelvic obliquity (contralateral pelvis rise/drop), lateral pelvic translation (ipsilateral/contralateral shift) and ipsilateral trunk lean during preparation for leg lift and average values in steady single leg stance, were compared between groups using an analysis of covariance, with and without anthropometric characteristics and strength as covariates. Individuals with gluteal tendinopathy demonstrated greater hip adduction (standardized mean difference (SMD)=0.70, P=0.04) and ipsilateral pelvic shift (SMD=1.1, P=0.002) in preparation for leg lift, and greater hip adduction (SMD=1.2, P=0.002) and less contralateral pelvic rise (SMD=0.86, P=0.02) in steady single leg stance than controls. When including strength as a covariate, only between-group differences in lateral pelvic shift persisted (SMD=1.7, P=0.01). Individuals with gluteal tendinopathy use different frontal plane kinematics of the hip and pelvis during single leg stance than pain-free controls. This finding is not influenced by pelvic dimension or the potentially modifiable factor of body mass index, but is by hip abductor muscle weakness. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Discriminant musculo-skeletal leg characteristics between sprint and endurance elite Caucasian runners.

    Science.gov (United States)

    Bex, T; Iannaccone, F; Stautemas, J; Baguet, A; De Beule, M; Verhegghe, B; Aerts, P; De Clercq, D; Derave, W

    2017-03-01

    Excellence in either sprinting or endurance running requires specific musculo-skeletal characteristics of the legs. This study aims to investigate the morphology of the leg of sprinters and endurance runners of Caucasian ethnicity. Eight male sprinters and 11 male endurance runners volunteered to participate in this cross-sectional study. They underwent magnetic resonance imaging and after data collection, digital reconstruction was done to calculate muscle volumes and bone lengths. Sprinters have a higher total upper leg volume compared to endurance runners (7340 vs 6265 cm 3 ). Specifically, the rectus femoris, vastus lateralis, and hamstrings showed significantly higher muscle volumes in the sprint group. For the lower leg, only a higher muscle volume was found in the gastrocnemius lateralis for the sprinters. No differences were found in muscle volume distribution, center of mass in the different muscles, or relative bone lengths. There was a significant positive correlation between ratio hamstrings/quadriceps volume and best running performance in the sprint group. Sprinters and endurance runners of Caucasian ethnicity showed the greatest distinctions in muscle volumes, rather than in muscle distributions or skeletal measures. Sprinters show higher volumes in mainly the proximal and lateral leg muscles than endurance runners. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  18. Decreased muscle mass in Korean subjects with intracranial arterial stenosis: The Kangbuk Samsung Health Study.

    Science.gov (United States)

    Jung, Ho-Jung; Jung, Hwanseok; Lee, Taeyoung; Kim, Jongho; Park, Jongsin; Kim, Hacsoo; Cho, Junghwan; Lee, Won-Young; Park, Sung-Woo; Rhee, Eun-Jung; Oh, Hyung-Geun

    2017-01-01

    Intracranial arterial stenosis (ICAS) is a common cause of ischemic stroke in Asians. Decreased muscle mass is one of the major causes of chronic disease in adults. The purpose of this study was to analyze the relationship between muscle mass and ICAS in Korean adults. For this study, we selected a total of 10,530 participants (mean age, 43.3 years; 8558 men) in a health screening program, for whom transcranial Doppler (TCD) ultrasound was used to detect >50% ICAS based on criteria modified from the stroke outcomes and neuroimaging of intracranial atherosclerosis trial. Body composition was evaluated by bioelectrical impedance analysis (BIA). Skeletal muscle index (SMI) was calculated with muscle mass/weight (kg) * 100. Among the total patient population, 322 (3.1%) subjects had ICAS. Subjects with ICAS were older, and had higher mean values for fasting glucose, body mass index and blood pressure compared with those without ICAS. Subjects with ICAS had significantly lower muscle mass, SMI and higher percent body fat compared with those without ICAS. In logistic regression analysis, the subjects in the highest tertile of muscle mass had the lowest odds ratio for ICAS with the lowest tertile group of muscle mass as the reference group even after adjusting for age, systolic blood pressure, fasting blood glucose, sex, smoking and exercise (OR 0.650, 95% CI 0.442-0.955). Subjects with ICAS had significantly decreased muscle mass compared with those without ICAS in Korean adults. The risk for ICAS was lower in subjects with higher muscle mass. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  19. Association between healthy diet and exercise and greater muscle mass in older adults.

    Science.gov (United States)

    Kim, Jinhee; Lee, Yunhwan; Kye, Seunghee; Chung, Yoon-Sok; Kim, Kwang-Min

    2015-05-01

    To examine the association between healthy diet and exercise, individually and combined, and low muscle mass in older Korean adults. Population-based cross-sectional study from the Fourth and Fifth Korea National Health and Nutrition Examination Surveys from 2008 to 2011. Community. Nationally representative sample aged 65 and older (1,486 men, 1,799 women) in the Republic of Korea. A food frequency questionnaire was used to determine frequency of food group consumption (meat, fish, eggs, legumes; vegetables; fruits). Participation in exercise (aerobic and resistance) was based on self-report. Combined healthy lifestyle factors were calculated as the number of recommendations met regarding consumption of food groups and exercise performed. Appendicular skeletal muscle mass (ASM) was measured using dual-energy X-ray absorptiometry, and low muscle mass was defined using the variable of ASM adjusted for weight. Logistic regression analysis was performed to examine the association between healthy lifestyle factors and low muscle mass, adjusting for sociodemographic characteristics and health-related variables. In women, after controlling for covariates, vegetable consumption (odds ratio (OR)=0.52, 95% confidence interval (CI)=0.30-0.89) and aerobic exercise (OR=0.62, 95% CI=0.39-1.00) were inversely associated with low muscle mass. Also, the odds of low muscle mass was lower in women with three or more healthy lifestyle factors versus none (OR=0.45, 95% CI=0.23-0.87). In men, there were no associations between food group consumption and exercise and low muscle mass. Older women who exercise and consume a healthy diet have lower odds of low muscle mass. Engaging in multiple healthy behaviors may be important in preventing low muscle mass in late life. © 2015, Copyright the Authors Journal compilation © 2015, The American Geriatrics Society.

  20. The bone morphogenetic protein axis is a positive regulator of skeletal muscle mass

    Science.gov (United States)

    Chen, Justin L.; Qian, Hongwei; Liu, Yingying; Bernardo, Bianca C.; Beyer, Claudia; Watt, Kevin I.; Thomson, Rachel E.; Connor, Timothy; Turner, Bradley J.; McMullen, Julie R.; Larsson, Lars; McGee, Sean L.; Harrison, Craig A.

    2013-01-01

    Although the canonical transforming growth factor β signaling pathway represses skeletal muscle growth and promotes muscle wasting, a role in muscle for the parallel bone morphogenetic protein (BMP) signaling pathway has not been defined. We report, for the first time, that the BMP pathway is a positive regulator of muscle mass. Increasing the expression of BMP7 or the activity of BMP receptors in muscles induced hypertrophy that was dependent on Smad1/5-mediated activation of mTOR signaling. In agreement, we observed that BMP signaling is augmented in models of muscle growth. Importantly, stimulation of BMP signaling is essential for conservation of muscle mass after disruption of the neuromuscular junction. Inhibiting the phosphorylation of Smad1/5 exacerbated denervation-induced muscle atrophy via an HDAC4-myogenin–dependent process, whereas increased BMP–Smad1/5 activity protected muscles from denervation-induced wasting. Our studies highlight a novel role for the BMP signaling pathway in promoting muscle growth and inhibiting muscle wasting, which may have significant implications for the development of therapeutics for neuromuscular disorders. PMID:24145169

  1. Muscle strength can better differentiate between gradations of functional performance than muscle quality in healthy 50–70 y women

    OpenAIRE

    Francis, Peter; McCormack, William; Toomey, Clodagh; Lyons, Mark; Jakeman, Philip

    2017-01-01

    Objective It is not known which laboratory indices of muscle mass, strength or quality can distinguish functional performance in healthy middle aged women. The aim of this study was to (a) examine the association between upper leg lean tissue mass, knee extensor strength, muscle quality (strength per unit lean tissue mass) and functional performance and (b) to determine the utility of tertiles of muscle strength and muscle quality to distinguish gradations of functional capacity in healthy 50...

  2. Different Levels of Eccentric Resistance during Eight Weeks of Training Affect Muscle Strength and Lean Tissue Mass

    Science.gov (United States)

    English, K. L.; Loehr, J. A.; Lee, S. M. C.; Laughlin, M. S.; Hagan, R. D.

    2008-01-01

    Coupling concentric and eccentric muscle contractions appears to be important in the development of muscle strength and hypertrophy. The interim Resistive Exercise Device (iRED) currently used aboard the International Space Station does not seem to be as effective as free weight training in ambulatory subjects and has not completely protected against muscular deconditioning due to space flight. The lack of protection during space flight could be caused by iRED's proportionally lower eccentric resistance (60-70%) compared to concentric resistance. PURPOSE: To determine the effects of 8 wks of lower body resistive exercise training using five levels of eccentric resistance on muscle strength and lean tissue mass. METHODS: Forty untrained males (34.9 +/- 7 yrs, 80.9 +/- 9.8 kg, 178.2 +/- 7.1 cm; mean +/- SD) completed three 1-repetition maximum (1-RM) strength tests for both the supine leg press (LP) and supine heel raise (HR) prior to training; subjects were matched for LP strength and randomly assigned to one of five training groups. Concentric load (% 1-RM) was constant across groups during training, but each group trained with different levels of eccentric load (0%, 33%, 66%, 100%, or 138% of concentric). Subjects trained 3 d / wk for 8 wks using a periodized program for LP and HR based on percentages of the highest pre-training 1-RM. LP and HR 1-RM and leg lean mass (LLM; assessed by DEXA) were measured pre- and post-training. A two-way ANOVA was used to analyze all dependent measures. Tukey's post hoc tests were used to test significant main effects. Within group pre- to post-training changes were compared using paired t-tests with a Bonferroni adjustment. Statistical significance was set a priori at p 0.05. All data are expressed as mean +/- SE. RESULTS: LP 1-RM strength increased significantly in all groups pre- to post-training. The 138% group increase (20.1 +/- 3.7%) was significantly greater than the 0% (7.9 +/- 2.8%), 33% (7.7 +/- 4.6%), and 66% (7.5 +/- 4

  3. Efficacy of Nintendo Wii Training on Mechanical Leg Muscle Function and Postural Balance in Community-Dwelling Older Adults

    DEFF Research Database (Denmark)

    Jorgensen, Martin G; Laessoe, Uffe; Hendriksen, Carsten

    2013-01-01

    BACKGROUND: Older adults show increased risk of falling and major risk factors include impaired lower extremity muscle strength and postural balance. However, the potential positive effect of biofeedback-based Nintendo Wii training on muscle strength and postural balance in older adults is unknown....... METHODS: This randomized controlled trial examined postural balance and muscle strength in community-dwelling older adults (75±6 years) pre- and post-10 weeks of biofeedback-based Nintendo Wii training (WII, n = 28) or daily use of ethylene vinyl acetate copolymer insoles (controls [CON], n = 30). Primary...... end points were maximal muscle strength (maximal voluntary contraction) and center of pressure velocity moment during bilateral static stance. RESULTS: Intention-to-treat analysis with adjustment for age, sex, and baseline level showed that the WII group had higher maximal voluntary contraction...

  4. Effects of exercise and tea catechins on muscle mass, strength and walking ability in community-dwelling elderly Japanese sarcopenic women: a randomized controlled trial.

    Science.gov (United States)

    Kim, Hunkyung; Suzuki, Takao; Saito, Kyoko; Yoshida, Hideyo; Kojima, Narumi; Kim, Miji; Sudo, Motoki; Yamashiro, Yukari; Tokimitsu, Ichiro

    2013-04-01

    To investigate the effects of exercise and/or tea catechin supplementation on muscle mass, strength and walking ability in elderly Japanese women with sarcopenia. A total of 128 women aged over 75 years were defined as sarcopenic and randomly assigned into four groups: exercise and tea catechin supplementation (n = 32), exercise (n = 32), tea catechin supplementation (n = 32) or health education (n = 32). The exercise group attended a 60-min comprehensive training program twice a week and the tea catechin supplementation group ingested 350 mL of a tea beverage fortified with catechin daily for 3 months. Body composition was determined by bioelectrical impedance analysis. Interview data and functional fitness measurements, such as muscle strength, balance and walking ability, were collected at baseline and after the 3-month intervention. There were significant group × time interactions observed in timed up & go (P exercise + catechin group showed a significant effect (odds ratio 3.61, 95% confidence interval 1.05-13.66) for changes in the combined variables of leg muscle mass and usual walking speed compared with the health education group. The combination of exercise and tea catechin supplementation had a beneficial effect on physical function measured by walking ability and muscle mass. © 2012 Japan Geriatrics Society.

  5. Cyclosporin-A does not affect skeletal muscle mass during disuse and recovery

    Directory of Open Access Journals (Sweden)

    M.S. Aoki

    2006-02-01

    Full Text Available Cyclosporin-A (CsA is an immunosuppressive drug that acts as an inhibitor of calcineurin, a calcium phosphatase that has been suggested to play a role in skeletal muscle hypertrophy. The aim of the present study was to determine the effect of CsA administration (25 mg kg-1 day-1 on skeletal muscle mass and phenotype during disuse and recovery. Male Wistar rats received vehicle (N = 8 or CsA (N = 8 during hind limb immobilization (N = 8 and recovery (N = 8. Muscle weight (dry/wet and cross-sectional area were evaluated to verify the effect of CsA treatment on muscle mass. Muscle phenotype was assessed by histochemistry of myosin ATPase. CsA administration during immobilization and recovery did not change muscle/body weight ratio in the soleus (SOL or plantaris (PL. Regarding muscle phenotype, we observed a consistent slow-to-fast shift in all experimental groups (immobilized only, receiving CsA only, and immobilized receiving CsA as compared to control in both SOL and PL (P < 0.05. During recovery, no difference was observed in SOL or PL fiber type composition between the experimental recovered group and recovered group receiving CsA compared to their respective controls. Considering the muscle/body weight ratio, CsA administration does not maximize muscle mass loss induced by immobilization. Our results also indicate that CsA fails to block skeletal muscle regrowth after disuse. The present data suggest that calcineurin inhibition by CsA modulates muscle phenotype rather than muscle mass.

  6. Protein turnover in the breast muscle of broiler chicks and studies addressing chlorine dioxide sanitation of hatching eggs, poultry leg problems and wheat middling diets for laying hens

    Energy Technology Data Exchange (ETDEWEB)

    Patterson, P.H.

    1988-01-01

    Developmental changes occurred in breast muscle Ks measured by {sup 14}C-tyrosine incorporation at 10, 16, 22 and 34 days of age. Protein synthesis rates decreased as the birds matures: 30 to 11.2%/d between 10 and 34 days of age. In a second study birds fed diets low in lysine or protein-energy had reduced fractional rates of protein synthesis and free tyrosine, branched chain and large neutral amino acid concentrations as compared to control birds the same body weight. Artificial weight loading and reduced dietary protein levels were used to study the effects of body weight on the severity of leg deformities in chicks and poults. Experiments investigating the practicality of wheat middlings as an alternate feedstuff for laying hens suggested that high levels in the diet will reduce egg production, feed conversion, hen livability and egg yolk color. Lastly, chlorine dioxide foam and dipping solutions were compared with formaldehyde fumigation for sanitizing hatching eggs.

  7. Protein turnover in the breast muscle of broiler chicks and studies addressing chlorine dioxide sanitation of hatching eggs, poultry leg problems and wheat middling diets for laying hens

    International Nuclear Information System (INIS)

    Patterson, P.H.

    1988-01-01

    Developmental changes occurred in breast muscle Ks measured by 14 C-tyrosine incorporation at 10, 16, 22 and 34 days of age. Protein synthesis rates decreased as the birds matures: 30 to 11.2%/d between 10 and 34 days of age. In a second study birds fed diets low in lysine or protein-energy had reduced fractional rates of protein synthesis and free tyrosine, branched chain and large neutral amino acid concentrations as compared to control birds the same body weight. Artificial weight loading and reduced dietary protein levels were used to study the effects of body weight on the severity of leg deformities in chicks and poults. Experiments investigating the practicality of wheat middlings as an alternate feedstuff for laying hens suggested that high levels in the diet will reduce egg production, feed conversion, hen livability and egg yolk color. Lastly, chlorine dioxide foam and dipping solutions were compared with formaldehyde fumigation for sanitizing hatching eggs

  8. Leg vascular and skeletal muscle mitochondrial adaptations to aerobic high-intensity exercise training are enhanced in the early postmenopausal phase

    DEFF Research Database (Denmark)

    Nyberg, Michael Permin; Egelund, Jon; Mandrup Jensen, Camilla Maria

    2017-01-01

    the haemodynamic response to acute exercise in matched pre- and postmenopausal women before and after 12 weeks of aerobic high intensity exercise training. Twenty premenopausal and 16 early postmenopausal (3.1 ± 0.5 [mean ± SEM] years after final menstrual period) women only separated by 4 (50 ± 0 versus 54 ± 1......Exercise training leads to favourable adaptations within skeletal muscle; however, this effect of exercise training may be blunted in postmenopausal women due to the loss of oestrogens. Furthermore, postmenopausal women may have an impaired vascular response to acute exercise. We examined......) years of age were included. Before training, leg blood flow, O2 delivery, O2 uptake, and lactate release during knee-extensor exercise were similar in pre- and postmenopausal women. Exercise training reduced (P

  9. Exercise and Amino Acid Anabolic Cell Signaling and the Regulation of Skeletal Muscle Mass

    Directory of Open Access Journals (Sweden)

    Stefan M. Pasiakos

    2012-07-01

    Full Text Available A series of complex intracellular networks influence the regulation of skeletal muscle protein turnover. In recent years, studies have examined how cellular regulators of muscle protein turnover modulate metabolic mechanisms contributing to the loss, gain, or conservation of skeletal muscle mass. Exercise and amino acids both stimulate anabolic signaling potentially through several intracellular pathways including the mammalian target of rapamycin complex 1 and the mitogen activated protein kinase cell signaling cascades. As novel molecular regulators of muscle integrity continue to be explored, a contemporary analysis of the literature is required to understand the metabolic mechanisms by which contractile forces and amino acids affect cellular process that contribute to long-term adaptations and preservation of muscle mass. This article reviews the literature related to how exercise and amino acid availability affect cellular regulators of skeletal muscle mass, especially highlighting recent investigations that have identified mechanisms by which contractile forces and amino acids modulate muscle health. Furthermore, this review will explore integrated exercise and nutrition strategies that promote the maintenance of muscle health by optimizing exercise, and amino acid-induced cell signaling in aging adults susceptible to muscle loss.

  10. Muscle mitochondrial capacity exceeds maximal oxygen delivery in humans

    DEFF Research Database (Denmark)

    Boushel, Robert Christopher; Gnaiger, Erich; Calbet, Jose A L

    2011-01-01

    Across a wide range of species and body mass a close matching exists between maximal conductive oxygen delivery and mitochondrial respiratory rate. In this study we investigated in humans how closely in-vivo maximal oxygen consumption (VO(2) max) is matched to state 3 muscle mitochondrial...... O(2) kg(-1) min(-1), exceeding the in-vivo leg VO(2) max (5.0±0.2 mmol O(2) kg(-1) min(-1)) during leg cycling with 20 kg muscle (P...... respiration. High resolution respirometry was used to quantify mitochondrial respiration from the biopsies of arm and leg muscles while in-vivo arm and leg VO(2) were determined by the Fick method during leg cycling and arm cranking. We hypothesized that muscle mitochondrial respiratory rate exceeds...

  11. The Impact of Low Muscle Mass Definition on the Prevalence of Sarcopenia in Older Australians

    Directory of Open Access Journals (Sweden)

    Solomon Yu

    2014-01-01

    Full Text Available Background. Sarcopenia is the presence of low muscle mass and low muscle function. The aim of this study was to establish cutoffs for low muscle mass using three published methods and to compare the prevalence of sarcopenia in older Australians. Methods. Gender specific cutoffs levels were identified for low muscle mass using three different methods. Low grip strength was determined using established cutoffs of <30 kg for men and <20 kg for women to estimate the prevalence of sarcopenia. Results. Gender specific cutoffs levels for low muscle mass identified were (a <6.89 kg/m2 for men and <4.32 kg/m2 for women, <2 standard deviation (SD of a young reference population; (b <7.36 kg/m2 for men and <5.81 kg/m2 for women from the lowest 20% percentile of the older group; and (c <−2.15 for men and <−1.42 for women from the lowest 20% of the residuals of linear regressions of appendicular skeletal mass, adjusted for fat mass and height. Prevalence of sarcopenia in older (65 years and older people by these three methods for men was 2.5%, 6.2%, and 6.4% and for women 0.3%, 9.3%, and 8.5%, respectively. Conclusions. Sarcopenia is common but consensus on the best method to confirm low muscle mass is required.

  12. The AMPK-related kinase SNARK regulates muscle mass and myocyte survival

    Science.gov (United States)

    The maintenance of skeletal muscle mass is critical for sustaining health; however, the mechanisms responsible for muscle loss with aging and chronic diseases, such as diabetes and obesity, are poorly understood. We found that expression of a member of the AMPK-related kinase family, the SNF1-AMPK-r...

  13. Alterations in molecular muscle mass regulators after 8 days immobilizing Special Forces mission

    DEFF Research Database (Denmark)

    Jespersen, J G; Mikkelsen, U R; Nedergaard, A

    2015-01-01

    In military operations, declined physical capacity can endanger the life of soldiers. During special support and reconnaissance (SSR) missions, Special Forces soldiers sustain 1-2 weeks full-body horizontal immobilization, which impairs muscle strength and performance. Adequate muscle mass and st...

  14. Deficits in muscle strength, mass, quality and mobility in people with chronic obstructive pulmonary disease

    DEFF Research Database (Denmark)

    Roig, Marc; Eng, Janice J; MacIntyre, Donna L

    2011-01-01

    PURPOSE: Midthigh intramuscular fat (IF), a feature of reduced muscle quality, is an important predictor of self-reported mobility loss in the elderly. This study compared measures of muscle strength, mass, IF, and mobility in patients with chronic obstructive pulmonary disease (COPD) and healthy...

  15. Mechanistic Links Underlying the Impact of C-Reactive Protein on Muscle Mass in Elderly.

    Science.gov (United States)

    Wåhlin-Larsson, Britta; Wilkinson, Daniel J; Strandberg, Emelie; Hosford-Donovan, Adrian; Atherton, Philip J; Kadi, Fawzi

    2017-01-01

    Mechanisms underlying the relationship between systemic inflammation and age-related decline in muscle mass are poorly defined. The purpose of this work was to investigate the relationship between the systemic inflammatory marker CRP and muscle mass in elderly and to identify mechanisms by which CRP mediates its effects on skeletal muscle, in-vitro. Muscle mass and serum CRP level were determined in a cohort of 118 older women (67±1.7 years). Human muscle cells were differentiated into myotubes and were exposed to CRP. The size of myotubes was determined after immunofluorescent staining using troponin. Muscle protein synthesis was assessed using stable isotope tracers and key signalling pathways controlling protein synthesis were determined using western-blotting. We observed an inverse relationship between circulating CRP level and muscle mass (β= -0.646 (95% CI: -0.888, -0.405) pmuscle protein fractional synthetic rate of human myotubes exposed to CRP for 24 h. We also identified a CRP-mediated increased phosphorylation (pprotein synthesis. This work established for the first time mechanistic links by which chronic elevation of CRP can contribute to age-related decline in muscle function. © 2017 The Author(s). Published by S. Karger AG, Basel.

  16. Avian pectoral muscle size rapidly tracks body mass changes during flight, fasting and fuelling

    NARCIS (Netherlands)

    Lindstrom, A; Kvist, A; Piersma, T; Dekinga, A; Dietz, MW; Lindström, Åke

    We used ultrasonic imaging to monitor short-term changes in the pectoral muscle size of captive red knots Calidris canutus. Pectoral muscle thickness changed rapidly and consistently in parallel with body mass changes caused by flight, fasting;and fuelling. Four knots hew repeatedly for 10h periods

  17. Levator claviculae muscle presenting as a hard clavicular mass: imaging study

    International Nuclear Information System (INIS)

    Ruiz Santiago, F.; Lopez Milena, G.; Tristan Fernandez, J.M.; Chamorro Santos, C.

    2001-01-01

    We report a case of levator claviculae muscle presenting clinically as a hard mass in the clavicular area due to angular deformity of this bone. To our knowledge, this is the first report where the anomalous muscle shows this clinical presentation. (orig.)

  18. Identification of hemostatic genes expressed in human and rat leg muscles and a novel gene (LPP1/PAP2A suppressed during prolonged physical inactivity (sitting

    Directory of Open Access Journals (Sweden)

    Zderic Theodore W

    2012-10-01

    Full Text Available Abstract Background Partly because of functional genomics, there has been a major paradigm shift from solely thinking of skeletal muscle as contractile machinery to an understanding that it can have roles in paracrine and endocrine functions. Physical inactivity is an established risk factor for some blood clotting disorders. The effects of inactivity during sitting are most alarming when a person develops the enigmatic condition in the legs called deep venous thrombosis (DVT or “coach syndrome,” caused in part by muscular inactivity. The goal of this study was to determine if skeletal muscle expresses genes with roles in hemostasis and if their expression level was responsive to muscular inactivity such as occurs in prolonged sitting. Methods Microarray analyses were performed on skeletal muscle samples from rats and humans to identify genes associated with hemostatic function that were significantly expressed above background based on multiple probe sets with perfect and mismatch sequences. Furthermore, we determined if any of these genes were responsive to models of physical inactivity. Multiple criteria were used to determine differential expression including significant expression above background, fold change, and non-parametric statistical tests. Results These studies demonstrate skeletal muscle tissue expresses at least 17 genes involved in hemostasis. These include the fibrinolytic factors tetranectin, annexin A2, and tPA; the anti-coagulant factors TFPI, protein C receptor, PAF acetylhydrolase; coagulation factors, and genes necessary for the posttranslational modification of these coagulation factors such as vitamin K epoxide reductase. Of special interest, lipid phosphate phosphatase-1 (LPP1/PAP2A, a key gene for degrading prothrombotic and proinflammatory lysophospholipids, was suppressed locally in muscle tissue within hours after sitting in humans; this was also observed after acute and chronic physical inactivity conditions

  19. Immobilization/remobilization and the regulation of muscle mass

    Science.gov (United States)

    Almon, R. R.

    1983-01-01

    The relationship between animal body weight and the wet and dry weights of the soleus and EDL muscles was derived. Procedures were examined for tissue homogenization, fractionation, protein determination and DNA determination. A sequence of procedures and buffers were developed to carry out all analyses on one small muscle. This would yield a considerable increase in analytical strength associated with paired statistics. The proposed casting procedure which was to be used for immobilization was reexamined.

  20. Myostatin inhibition in muscle, but not adipose tissue, decreases fat mass and improves insulin sensitivity.

    Directory of Open Access Journals (Sweden)

    Tingqing Guo

    Full Text Available Myostatin (Mstn is a secreted growth factor expressed in skeletal muscle and adipose tissue that negatively regulates skeletal muscle mass. Mstn(-/- mice have a dramatic increase in muscle mass, reduction in fat mass, and resistance to diet-induced and genetic obesity. To determine how Mstn deletion causes reduced adiposity and resistance to obesity, we analyzed substrate utilization and insulin sensitivity in Mstn(-/- mice fed a standard chow. Despite reduced lipid oxidation in skeletal muscle, Mstn(-/- mice had no change in the rate of whole body lipid oxidation. In contrast, Mstn(-/- mice had increased glucose utilization and insulin sensitivity as measured by indirect calorimetry, glucose and insulin tolerance tests, and hyperinsulinemic-euglycemic clamp. To determine whether these metabolic effects were due primarily to the loss of myostatin signaling in muscle or adipose tissue, we compared two transgenic mouse lines carrying a dominant negative activin IIB receptor expressed specifically in adipocytes or skeletal muscle. We found that inhibition of myostatin signaling in adipose tissue had no effect on body composition, weight gain, or glucose and insulin tolerance in mice fed a standard diet or a high-fat diet. In contrast, inhibition of myostatin signaling in skeletal muscle, like Mstn deletion, resulted in increased lean mass, decreased fat mass, improved glucose metabolism on standard and high-fat diets, and resistance to diet-induced obesity. Our results demonstrate that Mstn(-/- mice have an increase in insulin sensitivity and glucose uptake, and that the reduction in adipose tissue mass in Mstn(-/- mice is an indirect result of metabolic changes in skeletal muscle. These data suggest that increasing muscle mass by administration of myostatin antagonists may be a promising therapeutic target for treating patients with obesity or diabetes.

  1. Effect of exercise-induced enhancement of the leg-extensor muscle-tendon unit capacities on ambulatory mechanics and knee osteoarthritis markers in the elderly.

    Directory of Open Access Journals (Sweden)

    Kiros Karamanidis

    Full Text Available Leg-extensor muscle weakness could be a key component in knee joint degeneration in the elderly because it may result in altered muscular control during locomotion influencing the mechanical environment within the joint. This work aimed to examine whether an exercise-induced enhancement of the triceps surae (TS and quadriceps femoris (QF muscle-tendon unit (MTU capacities would affect mechanical and biological markers for knee osteoarthritis in the elderly.Twelve older women completed a 14-week TS and QF MTU exercise intervention, which had already been established as increasing muscle strength and tendon stiffness. Locomotion mechanics and serum cartilage oligomeric matrix protein (COMP levels were examined during incline walking. MTU mechanical properties were assessed using simultaneously ultrasonography and dynamometry.Post exercise intervention, the elderly had higher TS and QF contractile strength and tendon-aponeurosis stiffness. Regarding the incline gait task, the subjects demonstrated a lower external knee adduction moment and lower knee adduction angular impulse during the stance phase post-intervention. Furthermore, post-intervention compared to pre-intervention, the elderly showed lower external hip adduction moment, but revealed higher plantarflexion pushoff moment. The changes in the external knee adduction moment were significantly correlated with the improvement in ankle pushoff function. Serum COMP concentration increased in response to the 0.5-h incline walking exercise with no differences in the magnitude of increment between pre- and post-intervention.This work emphasizes the important role played by the ankle pushoff function in knee joint mechanical loading during locomotion, and may justify the inclusion of the TS MTU in prevention programs aiming to positively influence specific mechanical markers for knee osteoarthritis in the elderly. However, the study was unable to show that COMP is amenable to change in the elderly

  2. In the unloaded lower leg, vibration extrudes venous blood out of the calf muscles probably by direct acceleration and without arterial vasodilation.

    Science.gov (United States)

    Zange, Jochen; Molitor, Sven; Illbruck, Agnes; Müller, Klaus; Schönau, Eckhard; Kohl-Bareis, Matthias; Rittweger, Jörn

    2014-05-01

    During vibration of the whole unloaded lower leg, effects on capillary blood content and blood oxygenation were measured in the calf muscle. The hypotheses predicted extrusion of venous blood by a tonic reflex contraction and that reactive hyperaemia could be observed after vibration. Twelve male subjects sat in front of a vibration platform with their right foot affixed to the platform. In four intervals of 3-min duration vibration was applied with a peak-to-peak displacement of 5 mm at frequencies 15 or 25 Hz, and two foot positions, respectively. Near infrared spectroscopy was used for measuring haemoglobin oxygen saturation (SmO2) and the concentration of total haemoglobin (tHb) in the medial gastrocnemius muscle. Within 30 s of vibration SmO2 increased from 55 ± 1 to 66 ± 1 % (mean ± SE). Within 1.5 min afterwards SmO2 decreased to a steady state (62 ± 1 %). During the following 3 min of recovery SmO2 slowly decreased back to base line. THb decreased within the first 30 s of vibration, remained almost constant until the end of vibration, and slowly recovered to baseline afterwards. No significant differences were found for the two vibration frequencies and the two foot positions. The relaxed and unloaded calf muscles did not respond to vibration with a remarkable reflex contraction. The acceleration by vibration apparently ejected capillary venous blood from the muscle. Subsequent recovery did not match with a reactive hyperaemia indicating that the mere mechanical stress did not cause vasodilation.

  3. Two weeks of one-leg immobilization decreases skeletal muscle respiratory capacity equally in young and elderly men

    DEFF Research Database (Denmark)

    Gram, Martin; Vigelsø Hansen, Andreas; Yokota, Takashi

    2014-01-01

    Physical inactivity affects human skeletal muscle mitochondrial oxidative capacity but the influence of aging combined with physical inactivity is not known. This study investigates the effect of two weeks of immobilization followed by six weeks of supervised cycle training on muscle oxidative...... capacity in 17 young (23±1years) and 15 elderly (68±1years) healthy men. We applied high-resolution respirometry in permeabilized fibers from muscle biopsies at inclusion after immobilization and training. Furthermore, protein content of mitochondrial complexes I-V, mitochondrial heat shock protein 70 (mt...... of VDAC, mtHSP70 and complexes I, II, IV and V decreased with immobilization and increased with retraining. Moreover, there was no overall difference in the response between the groups. When the intrinsic mitochondrial capacity was evaluated by normalizing respiration to citrate synthase activity...

  4. The effects of whole-body vibration training and vitamin D supplementation on muscle strength, muscle mass, and bone density in institutionalized elderly women: a 6-month randomized, controlled trial.

    Science.gov (United States)

    Verschueren, Sabine M P; Bogaerts, An; Delecluse, Christophe; Claessens, Albrecht L; Haentjens, Patrick; Vanderschueren, Dirk; Boonen, Steven

    2011-01-01

    Sarcopenia and osteoporosis represent a growing public health problem. We studied the potential benefit of whole-body vibration (WBV) training given a conventional or a high dose of daily vitamin D supplementation in improving strength, muscle mass, and bone density in postmenopausal women. In a 2 × 2 factorial-design trial, 113 institutionalized elderly females aged over 70 years (mean age 79.6 years) were randomly assigned either to a WBV or a no-training group, receiving either a conventional dose (880 IU/day) or a high dose (1600 IU/day) of vitamin D(3). The primary aim was to determine the effects of 6 months of WBV and/or vitamin D supplementation on isometric and dynamic strength, leg muscle mass, and hip bone mineral density (BMD). Additionally, the increase in 25-hydroxyvitamin D [25(OH)D] levels between conventional and high-dose supplementation was compared. After 6 months of treatment, dynamic muscle strength, hip BMD, and vitamin D serum levels improved significantly in all groups, whereas isometric strength and muscle mass did not change. When compared with no training, the WBV program did not result in additional improvements. When compared with 880 IU, a high dose of 1600 IU of vitamin D did result in higher serum vitamin D levels but did not result in additional improvements. In institutionalized women older than 70 years, the WBV training protocol tested is not more efficient in enhancing muscle mass, strength, and hip BMD compared with vitamin D supplementation. A higher dose of 1600 IU of vitamin D does not provide additional musculoskeletal benefit in this population compared with conventional doses. © 2011 American Society for Bone and Mineral Research.

  5. Dietary protein intake in elderly women: association with muscle and bone mass.

    Science.gov (United States)

    Genaro, Patrícia de Souza; Pinheiro, Marcelo de Medeiros; Szejnfeld, Vera Lúcia; Martini, Lígia Araújo

    2015-04-01

    An inadequate food intake, mainly with regard to protein intake, seems to contribute to a reduction of skeletal muscle and bone mass in the elderly. This study was undertaken to evaluate differences in protein intake in women with or without sarcopenia and verify the intake level that is related to a better bone and muscle mass. Elderly women older than 65 years with sarcopenia (n = 35) and without sarcopenia (n = 165) participated in the study. Assessment of bone mineral density of the lumbar spine and femur was taken, body composition was evaluated by dual-energy x-ray absorptiometry, and an evaluation of protein intake was performed through 3-day dietary records. Muscle, bone, and fat mass was significantly higher in women who had protein intake >1.2 g/kg/d. A lower intake of essential amino acids in women with sarcopenia was also observed. Protein and energy intake were significant predictors of muscle mass. The presence of osteoporosis was a predictor of muscle strength. In conclusion, the present study demonstrated that in elderly women, an adequate protein intake in terms of quality and quantity, without need of supplementation, could have a positive impact on bone mineral density, lean mass, and skeletal muscle mass. © 2014 American Society for Parenteral and Enteral Nutrition.

  6. Adiposity, muscle mass and muscle strength in relation to functional decline in older persons.

    NARCIS (Netherlands)

    Schaap, L.A.; Koster, A.; Visser, M.

    2013-01-01

    Aging is associated with changes in body composition and muscle strength. This review aimed to determine the relation between different body composition measures and muscle strength measures and functional decline in older men and women. By use of relevant databases (PubMed, Embase, and CINAHL) and

  7. Muscle Strength Rather Than Muscle Mass Is Associated With Standing Balance in Elderly Outpatients

    NARCIS (Netherlands)

    Bijlsma, A.Y.; Pasma, J.H.; Lambers, D.; Stijntjes, M.; Blauw, G. J.; Meskers, C.G.M.; Maier, A.B.

    2013-01-01

    Objectives: Assessment of the association of muscle characteristics with standing balance is of special interest, as muscles are a target for potential intervention (ie, by strength training). Design: Cross-sectional study. Setting: Geriatric outpatient clinic. Participants: The study included 197

  8. Oxidative capacity and glycogen content increase more in arm than leg muscle in sedentary women after intense training

    DEFF Research Database (Denmark)

    Nordsborg, Nikolai Baastrup; Connolly, Luke; Weihe, Pál

    2015-01-01

    =21) or a non-training control group (CON, n=20), the training groups completed three workouts per week for 15 weeks. Resting muscle biopsies were obtained from m. vastus lateralis and m. deltoideus before and after the intervention. After the training intervention, a larger (P

  9. DHEA enhances effects of weight training on muscle mass and strength in elderly women and men.

    Science.gov (United States)

    Villareal, Dennis T; Holloszy, John O

    2006-11-01

    The plasma levels of dehydroepiandrosterone (DHEA) and its sulfated form (DHEAS) decline approximately 80% between the ages of 25 and 75 yr. Muscle mass and strength also decrease with aging. Published data on the effects of DHEA replacement on muscle mass and strength are conflicting. The goals of this study were to determine whether DHEA replacement increases muscle mass and strength and/or enhances the effects of heavy resistance exercise in elderly women and men. We conducted a randomized, double-blind, placebo-controlled study of the effects of 10 mo of DHEA replacement therapy with the addition of weightlifting exercise training during the last 4 mo of the study (DHEA + exercise group, n = 29; placebo + exercise group, n = 27). DHEA alone for 6 mo did not significantly increase strength or thigh muscle volume. However, DHEA therapy potentiated the effect of 4 mo of weightlifting training on muscle strength, evaluated by means of one-repetition maximum measurement and Cybex dynamometry, and on thigh muscle volume, measured by magnetic resonance imaging. Serum insulin-like growth factor concentration increased in response to DHEA replacement. This study provides evidence that DHEA replacement has the beneficial effect of enhancing the increases in muscle mass and strength induced by heavy resistance exercise in elderly individuals.

  10. Hemodynamic changes in rat leg muscles during tourniquet-induced ischemia-reperfusion injury observed by near-infrared spectroscopy

    International Nuclear Information System (INIS)

    Kim, J G; Lee, J; Tromberg, B J; Brenner, M; Roe, J; Walters, T J

    2009-01-01

    In this study, we hypothesized that non-invasive continuous wave near-infrared spectroscopy (CWNIRS) can determine the severity or reversibility of muscle damage due to ischemia/reperfusion (I/R), and the results will be highly correlated with those from physical examination and histological analysis. To test this hypothesis, we performed CWNIRS measurements on two groups of male Sprague-Dawley rats (∼400 g) that underwent 2 h (n = 6) or 3 h (n = 7) of pneumatic tourniquet application (TKA). Tissue oxyhemoglobin [HbO 2 ] and deoxyhemoglobin [Hb] concentration changes were monitored during the 2 h or 3 h of 250 mmHg TKA and for an additional 2 h post-TKA. Rats were euthanized 24 h post-TKA and examined for injury, edema and viability of muscles. Contralateral muscles served as controls for each animal. In both groups, [HbO 2 ] dropped immediately, then gradually decreased further after TKA and then recovered once the tourniquet was released. However, releasing after 2 h of TKA caused [HbO 2 ] to overshoot above the baseline during reperfusion while the 3 h group continued to have lower [HbO 2 ] than baseline. We found a significant correlation between the elapsed time from tourniquet release to the first recovery peak of [HbO 2 ] and the muscle weight ratio between tourniquet and contralateral limb muscles (R = 0.86). Hemodynamic patterns from non-invasive CWNIRS demonstrated significant differences between 2 h and 3 h I/R. The results demonstrate that CWNIRS may be useful as a non-invasive prognostic tool for conditions involving vascular compromise such as extremity compartment syndrome

  11. On the potential of lower limb muscles to accelerate the body's centre of mass during walking.

    Science.gov (United States)

    Correa, Tomas A; Pandy, Marcus G

    2013-01-01

    Quantification of lower limb muscle function during gait or other common activities may be achieved using an induced acceleration analysis, which determines the contributions of individual muscles to the accelerations of the body's centre of mass. However, this analysis is reliant on a mathematical optimisation for the distribution of net joint moments among muscles. One approach that overcomes this limitation is the calculation of a muscle's potential to accelerate the centre of mass based on either a unit-force or maximum-activation assumption. Unit-force muscle potential accelerations are determined by calculating the accelerations induced by a 1 N muscle force, whereas maximum-activation muscle potential accelerations are determined by calculating the accelerations induced by a maximally activated muscle. The aim of this study was to describe the acceleration potentials of major lower limb muscles during normal walking obtained from these two techniques, and to evaluate the results relative to absolute (optimisation-based) muscle-induced accelerations. Dynamic simulations of walking were generated for 10 able-bodied children using musculoskeletal models, and potential- and absolute induced accelerations were calculated using a perturbation method. While the potential accelerations often correctly identified the major contributors to centre-of-mass acceleration, they were noticeably different in magnitude and timing from the absolute induced accelerations. Potential induced accelerations predicted by the maximum-activation technique, which accounts for the force-generating properties of muscle, were no more consistent with absolute induced accelerations than unit-force potential accelerations. The techniques described may assist treatment decisions through quantitative analyses of common gait abnormalities and/or clinical interventions.

  12. Deficits in muscle strength, mass, quality, and mobility in people with chronic obstructive pulmonary disease.

    Science.gov (United States)

    Roig, Marc; Eng, Janice J; MacIntyre, Donna L; Road, Jeremy D; Reid, Wendy D

    2011-01-01

    Midthigh intramuscular fat (IF), a feature of reduced muscle quality, is an important predictor of self-reported mobility loss in the elderly. This study compared measures of muscle strength, mass, IF, and mobility in patients with chronic obstructive pulmonary disease (COPD) and healthy subjects. Associations between measures of muscle strength, mass, IF, and mobility were explored. Knee extensor muscle strength was assessed with an isokinetic dynamometer. Cross-sectional area and IF of the thigh muscles were measured with computerized tomography. Mobility was assessed with the repetitive sit-to-stand, self-selected gait speed, and 6-minute walk tests. Patients with COPD (n = 21, age 71.3 ± 8.1 years, and a percentage predicted force expiratory volume in 1 second of 47.2 ± 12.9) and 21 healthy subjects matched for age (67.4 ± 8.6 years), gender, and body mass participated in the study. Patients with COPD showed reduced average knee extensor strength (29%, P = .016) cross-sectional area of the thigh muscles (17%, P = .007) and mobility measures (~23%, P ≤ .001). Knee extensor and flexor IF was 2-folds greater in people with COPD (P ≤ .005). Measures of knee extensor muscle strength, mass, and IF were not associated with mobility measures. Compared with healthy controls, patients with moderate to severe COPD show marked deficits in muscle strength, mass, quality, and mobility. More studies with larger sample size are required to elucidate whether any of these muscle deficits can explain mobility impairments in COPD.

  13. The Effects of Muscle Mass on Homocyst(e)ine Levels in Plasma and Urine.

    Science.gov (United States)

    Malinow, M René; Lister, Craig L; DE Crée, Carl

    The present study was designed to examine the relationship between homocyst(e)ine (H[e]) levels and muscle mass. Two experimental groups each of 24 Caucasian males, one consisting of higher-muscle mass subjects (HMM) and the other of lower-muscle mass subjects (LMM) participated in this study. Muscle mass was estimated from 24-hour urine collections of creatinine (Crt). Muscle mass was 40.3 ± 15.9 kg in HMM and 37.2 ± 11.4 kg in LMM (P= 0.002). Mean plasma H(e) levels in HMM were 10.29 ± 2.9 nmol/mL, and in LMM were 10.02 ± 2.4 nmol/L (Not significant, [NS]). Urinary H(e) levels (UH[e]) were 9.95 ± 4.3 nmol/mL and 9.22 ± 2.9 nmol/mL for HMM and LMM, respectively (NS). Plasma H(e) levels correlated well with UH(e) (HMM: r= 0.58, P= 0.009; LMM: r= 0.66, P= 0.004). Muscle mass and was not correlated to either plasma H(e) or UH(e). However, in HMM trends were identified for body mass to be correlated with UH(e) (r= 0.39, P= 0.10) and UCrt (r= 0.41, P= 0.08). Surprisingly, in HMM plasma and UCrt were only weakly correlated (r= 0.44, P= 0.06). Our results do not support a causal relationship between the amount of muscle mass and H(e) levels in plasma or urine.

  14. A Tricuspid Valve Mass Attached to Papillary Muscle | Sabzi ...

    African Journals Online (AJOL)

    BACKGROUND: Cardiac myxoma is the most common benign heart tumor which can arise in any of the cardiac chambers, valves or related great veins. Diagnosis of a myxoma arising from the tricuspid valve apparatus is exceptional. We present a rare case of myxoma in a tricuspid valve attached to papillary muscle.

  15. Skeletal muscle mass and composition during mammalian hibernation.

    Science.gov (United States)

    Cotton, Clark J

    2016-01-01

    Hibernation is characterized by prolonged periods of inactivity with concomitantly low nutrient intake, conditions that would typically result in muscle atrophy combined with a loss of oxidative fibers. Yet, hibernators consistently emerge from winter with very little atrophy, frequently accompanied by a slight shift in fiber ratios to more oxidative fiber types. Preservation of muscle morphology is combined with down-regulation of glycolytic pathways and increased reliance on lipid metabolism instead. Furthermore, while rates of protein synthesis are reduced during hibernation, balance is maintained by correspondingly low rates of protein degradation. Proposed mechanisms include a number of signaling pathways and transcription factors that lead to increased oxidative fiber expression, enhanced protein synthesis and reduced protein degradation, ultimately resulting in minimal loss of skeletal muscle protein and oxidative capacity. The functional significance of these outcomes is maintenance of skeletal muscle strength and fatigue resistance, which enables hibernating animals to resume active behaviors such as predator avoidance, foraging and mating immediately following terminal arousal in the spring. © 2016. Published by The Company of Biologists Ltd.

  16. A practical approach to assess leg muscle oxygenation during ramp-incremental cycle ergometry in heart failure

    Directory of Open Access Journals (Sweden)

    A.C. Barroco

    2017-10-01

    Full Text Available Heart failure is characterized by the inability of the cardiovascular system to maintain oxygen (O2 delivery (i.e., muscle blood flow in non-hypoxemic patients to meet O2 demands. The resulting increase in fractional O2 extraction can be non-invasively tracked by deoxygenated hemoglobin concentration (deoxi-Hb as measured by near-infrared spectroscopy (NIRS. We aimed to establish a simplified approach to extract deoxi-Hb-based indices of impaired muscle O2 delivery during rapidly-incrementing exercise in heart failure. We continuously probed the right vastus lateralis muscle with continuous-wave NIRS during a ramp-incremental cardiopulmonary exercise test in 10 patients (left ventricular ejection fraction <35% and 10 age-matched healthy males. Deoxi-Hb is reported as % of total response (onset to peak exercise in relation to work rate. Patients showed lower maximum exercise capacity and O2 uptake-work rate than controls (P<0.05. The deoxi-Hb response profile as a function of work rate was S-shaped in all subjects, i.e., it presented three distinct phases. Increased muscle deoxygenation in patients compared to controls was demonstrated by: i a steeper mid-exercise deoxi-Hb-work rate slope (2.2±1.3 vs 1.0±0.3% peak/W, respectively; P<0.05, and ii late-exercise increase in deoxi-Hb, which contrasted with stable or decreasing deoxi-Hb in all controls. Steeper deoxi-Hb-work rate slope was associated with lower peak work rate in patients (r=–0.73; P=0.01. This simplified approach to deoxi-Hb interpretation might prove useful in clinical settings to quantify impairments in O2 delivery by NIRS during ramp-incremental exercise in individual heart failure patients.

  17. Medium-latency stretch reflexes of foot and leg muscles analysed by cooling the lower limb in standing humans.

    Science.gov (United States)

    Schieppati, M; Nardone, A

    1997-09-15

    1. In standing subjects, an ankle-dorsiflexing perturbation of the supporting surface evokes a short-latency response (SLR) and a medium-latency response (MLR) to stretch in both soleus (Sol) and flexor digitorum brevis (FDB) muscles. The SLR is the counterpart of the monosynaptic reflex, whilst the MLR might be either mediated by Ia fibres, the delay being due to a long-loop central circuit, or by fibres of slower conduction velocity. Since small afferents are slowed more than large ones by low temperature, a greater latency increment for the MLR than the SLR induced by cooling of the limb would point to a peripheral origin of the MLR. 2. In nine subjects, one limb was cooled by circulating water in a tube wrapped around it for about 120 min. Perturbations were delivered to the same limb prior to and during cooling, and after rewarming. EMG was recorded by surface electrodes from the Sol and FDB muscles. 3. The mean increase in latency of MLRs was significantly greater than that of SLRs in both muscles. On average, the Sol SLR increased from 42.4 to 47.0 ms and the Sol MLR from 72.0 to 82.3 ms. The FDB SLR increased from 58.1 to 66.5 ms and the FDB MLR from 94.9 to 110.5 ms. The mean difference (MLR minus SLR) increased from 29.6 to 35.2 ms for Sol, and from 36.8 to 43.9 ms for FDB at the end of cooling. After 30 min of rewarming, the responses of both muscles recovered towards control values. 4. The greater latency increment of the MLRs than of the SLRs favours the hypothesis of a slower conduction velocity of the responsible afferent fibres. The most likely candidate fibres are the spindle group II afferents.

  18. Comparisons between low-intensity resistance training with blood flow restriction and high-intensity resistance training on quadriceps muscle mass and strength in elderly.

    Science.gov (United States)

    Vechin, Felipe C; Libardi, Cleiton A; Conceição, Miguel S; Damas, Felipe R; Lixandrão, Manoel E; Berton, Ricardo P B; Tricoli, Valmor A A; Roschel, Hamilton A; Cavaglieri, Claudia R; Chacon-Mikahil, Mara Patricia T; Ugrinowitsch, Carlos

    2015-04-01

    High-intensity resistance training (HRT) has been recommended to offset age-related loss in muscle strength and mass. However, part of the elderly population is often unable to exercise at high intensities. Alternatively, low-intensity resistance training with blood flow restriction (LRT-BFR) has emerged. The purpose of this study was to compare the effects of LRT-BFR and HRT on quadriceps muscle strength and mass in elderly. Twenty-three elderly individuals, 14 men and 9 women (age, 64.04 ± 3.81 years; weight, 72.55 ± 16.52 kg; height, 163 ± 11 cm), undertook 12 weeks of training. Subjects were ranked according to their pretraining quadriceps cross-sectional area (CSA) values and then randomly allocated into one of the following groups: (a) control group, (b) HRT: 4 × 10 repetitions, 70-80% one repetition maximum (1RM), and (c) LRT-BFR: 4 sets (1 × 30 and 3 × 15 repetitions), 20-30% 1RM. The occlusion pressure was set at 50% of maximum tibial arterial pressure and sustained during the whole training session. Leg press 1RM and quadriceps CSA were evaluated at before and after training. A mixed-model analysis was performed, and the significance level was set at p ≤ 0.05. Both training regimes were effective in increasing pre- to post-training leg press 1RM (HRT: ∼54%, p strength gains. In summary, LRT-BFR constitutes an important surrogate approach to HRT as an effective training method to induce gains in muscle strength and mass in elderly.

  19. Increased gain of vestibulospinal potentials evoked in neck and leg muscles when standing under height-induced postural threat.

    Science.gov (United States)

    Naranjo, E N; Allum, J H J; Inglis, J T; Carpenter, M G

    2015-05-07

    To measure changes in amplitudes of vestibular evoked myogenic potentials (VEMPs) elicited from neck, upper and lower limb muscles during a quiet standing task with increased postural threat achieved by manipulating surface height. Twenty eight subjects were tested while standing on a platform raised to 0.8 m and 3.2 m from the ground. Surface electromyography was recorded from the ipsilateral sternocleidomastoid (SCM), biceps brachii (BB), flexor carpi radialis (FCR), soleus (SOL) and medial gastrocnemius (MG) muscles. Stimulation was with air-conducted short tone bursts (4 ms). After controlling for background muscle activity, VEMP amplitudes were compared between heights and correlated with changes in state anxiety, fear and arousal. VEMP amplitude significantly increased in SCM (9%) and SOL (12.7%) with increased surface height (pgains. Results demonstrate that VEMPs can be used to test different VSR pathways simultaneously during stance. Since fear and anxiety are prevalent with vestibular disorders, they should be considered as potential contributing factors for clinical vestibular outcome measures. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

  20. Pitfalls in the measurement of muscle mass: a need for a reference standard

    Science.gov (United States)

    Landi, Francesco; Cesari, Matteo; Fielding, Roger A.; Visser, Marjolein; Engelke, Klaus; Maggi, Stefania; Dennison, Elaine; Al‐Daghri, Nasser M.; Allepaerts, Sophie; Bauer, Jurgen; Bautmans, Ivan; Brandi, Maria Luisa; Bruyère, Olivier; Cederholm, Tommy; Cerreta, Francesca; Cherubini, Antonio; Cooper, Cyrus; Cruz‐Jentoft, Alphonso; McCloskey, Eugene; Dawson‐Hughes, Bess; Kaufman, Jean‐Marc; Laslop, Andrea; Petermans, Jean; Reginster, Jean‐Yves; Rizzoli, René; Robinson, Sian; Rolland, Yves; Rueda, Ricardo; Vellas, Bruno; Kanis, John A.

    2018-01-01

    Abstract Background All proposed definitions of sarcopenia include the measurement of muscle mass, but the techniques and threshold values used vary. Indeed, the literature does not establish consensus on the best technique for measuring lean body mass. Thus, the objective measurement of sarcopenia is hampered by limitations intrinsic to assessment tools. The aim of this study was to review the methods to assess muscle mass and to reach consensus on the development of a reference standard. Methods Literature reviews were performed by members of the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis working group on frailty and sarcopenia. Face‐to‐face meetings were organized for the whole group to make amendments and discuss further recommendations. Results A wide range of techniques can be used to assess muscle mass. Cost, availability, and ease of use can determine whether the techniques are better suited to clinical practice or are more useful for research. No one technique subserves all requirements but dual energy X‐ray absorptiometry could be considered as a reference standard (but not a gold standard) for measuring muscle lean body mass. Conclusions Based on the feasibility, accuracy, safety, and low cost, dual energy X‐ray absorptiometry can be considered as the reference standard for measuring muscle mass. PMID:29349935

  1. The impact of low muscle mass definition on the prevalence of sarcopenia in older Australians.

    Science.gov (United States)

    Yu, Solomon; Appleton, Sarah; Adams, Robert; Chapman, Ian; Wittert, Gary; Visvanathan, Thavarajah; Visvanathan, Renuka

    2014-01-01

    Sarcopenia is the presence of low muscle mass and low muscle function. The aim of this study was to establish cutoffs for low muscle mass using three published methods and to compare the prevalence of sarcopenia in older Australians. Gender specific cutoffs levels were identified for low muscle mass using three different methods. Low grip strength was determined using established cutoffs of standard deviation (SD) of a young reference population; (b) <7.36 kg/m(2) for men and <5.81 kg/m(2) for women from the lowest 20% percentile of the older group; and (c) <-2.15 for men and <-1.42 for women from the lowest 20% of the residuals of linear regressions of appendicular skeletal mass, adjusted for fat mass and height. Prevalence of sarcopenia in older (65 years and older) people by these three methods for men was 2.5%, 6.2%, and 6.4% and for women 0.3%, 9.3%, and 8.5%, respectively. Sarcopenia is common but consensus on the best method to confirm low muscle mass is required.

  2. Low muscle mass in older men: the role of lifestyle, diet and cardiovascular risk factors.

    Science.gov (United States)

    Atkins, J L; Whincup, P H; Morris, R W; Wannamethee, S G

    2014-01-01

    To explore associations between low muscle mass and a wide range of lifestyle, dietary and cardiovascular risk factors in older men including metabolic risk factors, markers of inflammation, endothelial dysfunction and coagulation. Cross-sectional study. British Regional Heart Study. 4252 men aged 60-79 years. PARTICIPANTS attended a physical examination in 1998-2000, and completed a general questionnaire and a food frequency questionnaire. Low muscle mass was assessed by two measures: midarm muscle circumference (MAMC) and fat-free mass index (FFMI). Associations between risk factors and low muscle mass were analysed using logistic regression. Physical inactivity, insulin resistance, C-reactive protein, von Willebrand factor and fibrinogen were associated with significantly increased odds of low MAMC and FFMI after adjustment for body mass index, lifestyle characteristics and morbidity. Those with higher percent energy intake from carbohydrates showed decreased odds of low MAMC (OR: 0.73, 95% CI: 0.55-0.96) and FFMI (OR: 0.76, 95% CI: 0.58-0.99). Other dietary variables, smoking, alcohol intake, D-dimer, interleukin 6 and homocysteine showed no important associations with MAMC and FFMI. Increasing physical activity, consuming a diet with a high proportion of energy from carbohydrates, and taking steps to prevent insulin resistance and reduce inflammation and endothelial dysfunction may help to reduce the risk of low muscle mass in older men.

  3. Locomotion and muscle mass measures in a murine model of collagen-induced arthritis

    NARCIS (Netherlands)

    Hartog, A.; Hulsman, J.; Garssen, J.

    2009-01-01

    Background: Rheumatoid arthritis (RA) is characterized by chronic poly-arthritis, synovial hyperplasia, erosive synovitis, progressive cartilage and bone destruction accompanied by a loss of body cell mass. This loss of cell mass, known as rheumatoid cachexia, predominates in the skeletal muscle and

  4. Mechanistic Links Underlying the Impact of C-Reactive Protein on Muscle Mass in Elderly

    Directory of Open Access Journals (Sweden)

    Britta Wåhlin-Larsson

    2017-11-01

    Full Text Available Background/Aims: Mechanisms underlying the relationship between systemic inflammation and age-related decline in muscle mass are poorly defined. The purpose of this work was to investigate the relationship between the systemic inflammatory marker CRP and muscle mass in elderly and to identify mechanisms by which CRP mediates its effects on skeletal muscle, in-vitro. Methods: Muscle mass and serum CRP level were determined in a cohort of 118 older women (67±1.7 years. Human muscle cells were differentiated into myotubes and were exposed to CRP. The size of myotubes was determined after immunofluorescent staining using troponin. Muscle protein synthesis was assessed using stable isotope tracers and key signalling pathways controlling protein synthesis were determined using western-blotting. Results: We observed an inverse relationship between circulating CRP level and muscle mass (β= -0.646 (95% CI: -0.888, -0.405 p<0.05 and demonstrated a reduction (p < 0.05 in the size of human myotubes exposed to CRP for 72 h. We next showed that this morphological change was accompanied by a CRP-mediated reduction (p < 0.05 in muscle protein fractional synthetic rate of human myotubes exposed to CRP for 24 h. We also identified a CRP-mediated increased phosphorylation (p<0.05 of regulators of cellular energy stress including AMPK and downstream targets, raptor and ACC-β, together with decreased phosphorylation of Akt and rpS6, which are important factors controlling protein synthesis. Conclusion: This work established for the first time mechanistic links by which chronic elevation of CRP can contribute to age-related decline in muscle function.

  5. Growth hormone mitigates loss of periosteal bone formation and muscle mass in disuse osteopenic rats.

    Science.gov (United States)

    Grubbe, M-C; Thomsen, J S; Nyengaard, J R; Duruox, M; Brüel, A

    2014-12-01

    Growth hormone (GH) is a potent anabolic agent capable of increasing both bone and muscle mass. The aim was to investigate whether GH could counteract disuse-induced loss of bone and muscle mass in a rat model. Paralysis was induced by injecting 4 IU Botox (BTX) into the muscles of the right hind limb. Sixty female Wistar rats, 14 weeks old, were divided into the following groups: baseline, controls, BTX, BTX+GH, and GH. GH was given at a dosage of 5 mg/kg/d for 4 weeks. Compared with controls, BTX resulted in lower periosteal bone formation rate (BFR/BS,-79%, Pbone mineral density (aBMD, -13%, Pbone volume (BV/TV, -26%, Pbone strength (-12%, Pbone strength was found. In addition, GH partly prevented loss of muscle mass (+29% vs. BTX, P<0.001), and tended to prevent loss of muscle CSA (+11%, P=0.064). In conclusion, GH mitigates disuse-induced loss of periosteal BFR/BS at the mid-femur and rectus femoris muscle mass.

  6. Enhanced muscle blood flow with intermittent pneumatic compression of the lower leg during plantar flexion exercise and recovery.

    Science.gov (United States)

    Zuj, K A; Prince, C N; Hughson, R L; Peterson, S D

    2018-02-01

    This study tested the hypothesis that intermittent compression of the lower limb would increase blood flow during exercise and postexercise recovery. Data were collected from 12 healthy individuals (8 men) who performed 3 min of standing plantar flexion exercise. The following three conditions were tested: no applied compression (NoComp), compression during the exercise period only (ExComp), and compression during 2 min of standing postexercise recovery. Doppler ultrasound was used to determine superficial femoral artery (SFA) blood flow responses. Mean arterial pressure (MAP) and cardiac stroke volume (SV) were assessed using finger photoplethysmography, with vascular conductance (VC) calculated as VC = SFA flow/MAP. Compared with the NoComp condition, compression resulted in increased MAP during exercise [+3.5 ± 4.1 mmHg (mean ± SD)] but not during postexercise recovery (+1.6 ± 5.9 mmHg). SV increased with compression during both exercise (+4.8 ± 5.1 ml) and recovery (+8.0 ± 6.6 ml) compared with NoComp. There was a greater increase in SFA flow with compression during exercise (+52.1 ± 57.2 ml/min) and during recovery (+58.6 ± 56.7 ml/min). VC immediately following exercise was also significantly greater in the ExComp condition compared with the NoComp condition (+0.57 ± 0.42 ml·min -1 ·mmHg -1 ), suggesting the observed increase in blood flow during exercise was in part because of changes in VC. Results from this study support the hypothesis that intermittent compression applied during exercise and recovery from exercise results in increased limb blood flow, potentially contributing to changes in exercise performance and recovery. NEW & NOTEWORTHY Blood flow to working skeletal muscle is achieved in part through the rhythmic actions of the skeletal muscle pump. This study demonstrated that the application of intermittent pneumatic compression during the diastolic phase of the cardiac cycle, to mimic the mechanical

  7. Endogenous testosterone, muscle strength, and fat-free mass in men with chronic kidney disease.

    Science.gov (United States)

    Cigarrán, Secundino; Pousa, Montserrat; Castro, María Jesús; González, Berta; Martínez, Aurelia; Barril, Guillermina; Aguilera, Abelardo; Coronel, Francisco; Stenvinkel, Peter; Carrero, Juan Jesús

    2013-09-01

    Testosterone deficiency is a common finding in men with chronic kidney disease (CKD). Testosterone is thought to play an important anabolic role in muscle synthesis, and muscle wasting is an important and deleterious characteristic of protein-energy wasting (PEW) in CKD. It is presently unknown if reduced endogenous testosterone associates with features of muscle wasting in men with CKD. This was a cross-sectional observational study of 267 men with CKD stages 2-4 (mean ± standard deviation age 67 ± 13 years, estimated glomerular filtration rate 42.9 [interquartile range 30.2-56.7] mL/min/1.73 m²) with measurements of endogenous testosterone and surrogates of PEW such as albumin, prealbumin, high-sensitivity C-reactive protein (CRP) and normalized protein nitrogen appearance (nPNA). Fat-free mass was estimated by bioelectrical impedance vector analysis (BIVA) and muscle strength by handgrip dynamometry. Across decreasing thirds of testosterone distribution, patients were incrementally older and CRP levels rose significantly. Prealbumin, hemoglobin, nPNA, handgrip strength, and BIVA estimated surrogates of muscle mass and nutritional status (fat-free mass, body cell mass, and phase angle) were progressively reduced (P testosterone significantly and independently contributed to explain the variances of handgrip strength and fat-free mass (P testosterone independently associates with muscle strength and fat-free mass in men with moderate CKD. It is plausible that the reduction in testosterone levels that accompanies CKD may further contribute to the procatabolic environment leading to muscle wasting. Copyright © 2013 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

  8. Tinetti mobility test is related to muscle mass and strength in non-institutionalized elderly people.

    Science.gov (United States)

    Curcio, Francesco; Basile, Claudia; Liguori, Ilaria; Della-Morte, David; Gargiulo, Gaetano; Galizia, Gianluigi; Testa, Gianluca; Langellotto, Assunta; Cacciatore, Francesco; Bonaduce, Domenico; Abete, Pasquale

    2016-12-01

    Elderly people are characterized by a high prevalence of falls and sarcopenia. However, the relationship among Tinetti mobility test (TMT) score, a powerful tool to detect elderly people at risk of falls, and sarcopenia is still not thoroughly investigated. Thus, to determine the relationship between TMT score and muscle mass and strength, 337 elderly participants (mean age 77.1 ± 6.9 years) admitted to comprehensive geriatric assessment were enrolled. TMT score, muscle mass by bioimpedentiometer, and muscle strength by grip strength were evaluated. Muscle mass progressively decreased as TMT score decreased (from 15.3 ± 3.7 to 8.8 ± 1.8 kg/m 2 ; p for trend strength decreased progressively as Tinetti score decreased (from 34.7 ± 8.0 to 23.7 ± 8.7 kg; p for trend 0.001). Linear regression analysis demonstrated that TMT score is linearly related with muscle mass (y = 4.5x + 0.4, r = 0.61; p strength (y = 14.0x + 0.8, r = 0.53; p strength (r = 0.39, p = 0.046). The present study indicates that TMT score is significantly related to muscle mass and strength in non-institutionalized elderly participants. This evidence suggests that TMT score, together with evaluation of muscle mass and strength, may identify sarcopenic elderly participants at high risk of falls.

  9. Predicting muscle mass from anthropometry using magnetic resonance imaging as reference: a systematic review.

    Science.gov (United States)

    Al-Gindan, Yasmin Y; Hankey, Catherine R; Leslie, Wilma; Govan, Lindsay; Lean, Michael E J

    2014-02-01

    Identification and management of sarcopenia are limited by lack of reliable simple approaches to assess muscle mass. The aim of this review is to identify and evaluate simple methods to quantify muscle mass/volume of adults. Using Cochrane Review methodology, Medline (1946-2012), Embase (1974-2012), Web of Science (1898-2012), PubMed, and the Cochrane Library (to 08/2012) were searched for publications that included prediction equations (from anthropometric measurements) to estimate muscle mass by magnetic resonance imaging (MRI) in adults. Of 257 papers identified from primary search terms, 12 studies met the inclusion criteria. Most studies (n = 10) assessed only regional/limb muscle mass/volume. Many studies (n = 9) assessed limb circumference adjusted for skinfold thickness, which limits their practical applications. Only two included validation in separate subject-samples, and two reported relationships between whole-body MRI-measured muscle mass and anthropometry beyond linear correlations. In conclusion, one simple prediction equation shows promise, but it has not been validated in a separate population with different investigators. Furthermore, it did not incorporate widely available trunk/limb girths, which have offered valuable prediction of body composition in other studies. © 2014 International Life Sciences Institute.

  10. Impaired physical function, loss of muscle mass and assessment of biomechanical properties in critical ill patients

    DEFF Research Database (Denmark)

    Poulsen, Jesper Brøndum

    2012-01-01

    Intensive care unit (ICU) admission is associated with muscle weakness and ICU survivors report sustained limitation of physical capacity for years after discharge. Limited information is available on the underlying biomechanical properties responsible for this muscle function impairment. A plaus......Intensive care unit (ICU) admission is associated with muscle weakness and ICU survivors report sustained limitation of physical capacity for years after discharge. Limited information is available on the underlying biomechanical properties responsible for this muscle function impairment....... A plausible contributor to the accentuated catabolic drive in ICU patients is a synergistic response to inflammation and inactivity leading to loss of muscle mass. As these entities are predominantly present in the early phase of ICU stay, interventions employed during this time frame may exhibit the greatest...

  11. Effect of anabolic steroids on skeletal muscle mass during hindlimb suspension

    Science.gov (United States)

    Tsika, R. W.; Herrick, R. E.; Baldwin, K. M.

    1987-01-01

    The effect of treatment with an anabolic steroid (nandrolone decanoate) on the muscle mass of plantaris and soleus of a rats in hindlimb suspension, and on the isomyosin expression in these muscles, was investigated in young female rats divided into four groups: normal control (NC), normal steroid (NS), normal suspension (N-sus), and suspension steroid (sus-S). Steroid treatment of suspended animals (sus-S vs N-sus) was found to partially spare body weight and muscle weight, as well as myofibril content of plantaris (but not soleus), but did not modify the isomyosin pattern induced by suspension. In normal rats (NS vs NC), steroid treatment did enhance body weight and plantaris muscle weight; the treatment did not alter isomyosin expression in either muscle type.

  12. Blockade of Metallothioneins 1 and 2 Increases Skeletal Muscle Mass and Strength

    Science.gov (United States)

    Summermatter, Serge; Bouzan, Anais; Pierrel, Eliane; Melly, Stefan; Stauffer, Daniela; Gutzwiller, Sabine; Nolin, Erin; Dornelas, Christina; Fryer, Christy; Leighton-Davies, Juliet; Glass, David J.

    2016-01-01

    ABSTRACT Metallothioneins are proteins that are involved in intracellular zinc storage and transport. Their expression levels have been reported to be elevated in several settings of skeletal muscle atrophy. We therefore investigated the effect of metallothionein blockade on skeletal muscle anabolism in vitro and in vivo. We found that concomitant abrogation of metallothioneins 1 and 2 results in activation of the Akt pathway and increases in myotube size, in type IIb fiber hypertrophy, and ultimately in muscle strength. Importantly, the beneficial effects of metallothionein blockade on muscle mass and function was also observed in the setting of glucocorticoid addition, which is a strong atrophy-inducing stimulus. Given the blockade of atrophy and the preservation of strength in atrophy-inducing settings, these results suggest that blockade of metallothioneins 1 and 2 constitutes a promising approach for the treatment of conditions which result in muscle atrophy. PMID:27956698

  13. Absence of insulin signalling in skeletal muscle is associated with reduced muscle mass and function: evidence for decreased protein synthesis and not increased degradation.

    Science.gov (United States)

    O'Neill, Elaine D; Wilding, John P H; Kahn, C Ronald; Van Remmen, Holly; McArdle, Anne; Jackson, Malcolm J; Close, Graeme L

    2010-06-01

    Loss of skeletal muscle mass and function is observed in many insulin-resistant disease states such as diabetes, cancer cachexia, renal failure and ageing although the mechanisms for this remain unclear. We hypothesised that impaired insulin signalling results in reduced muscle mass and function and that this decrease in muscle mass and function is due to both increased production of atrogenes and aberrant reactive oxygen species (ROS) generation. Maximum tetanic force of the extensor digitorum longus of muscle insulin receptor knockout (MIRKO) and lox/lox control mice was measured in situ. Muscles were removed for the measurement of mass, histological examination and ROS production. Activation of insulin signalling pathways, markers of muscle atrophy and indices of protein synthesis were determined in a separate group of MIRKO and lox/lox mice 15 min following treatment with insulin. Muscles from MIRKO mice had 36% lower maximum tetanic force generation compared with muscles of lox/lox mice. Muscle fibres of MIRKO mice were significantly smaller than those of lox/lox mice with no apparent structural abnormalities. Muscles from MIRKO mice demonstrated absent phosphorylation of AKT in response to exogenous insulin along with a failure to phosphorylate ribosomal S6 compared with lox/lox mice. Atrogin-1 and MuRF1 relative mRNA expression in muscles from MIRKO mice were decreased compared with muscles from lox/lox mice following insulin treatment. There were no differences in markers of reactive oxygen species damage between muscles from MIRKO mice and lox/lox mice. These data support the hypothesis that the absence of insulin signalling contributes to reduced muscle mass and function though decreased protein synthesis rather than proteasomal atrophic pathways.

  14. The loss of skeletal muscle strength, mass, and quality in older adults : the health, aging and body composition study

    NARCIS (Netherlands)

    Goodpaster, Bret H; Park, Seok Won; Harris, Tamara B; Kritchevsky, Steven B; Nevitt, Michael; Schwartz, Ann V; Simonsick, Eleanor M; Tylavsky, Frances A; Visser, Marjolein; Newman, Anne B

    2006-01-01

    BACKGROUND: The loss of muscle mass is considered to be a major determinant of strength loss in aging. However, large-scale longitudinal studies examining the association between the loss of mass and strength in older adults are lacking. METHODS: Three-year changes in muscle mass and strength were

  15. Muscle mass as a target to reduce fatigue in patients with advanced cancer.

    Science.gov (United States)

    Neefjes, Elisabeth C W; van den Hurk, Renske M; Blauwhoff-Buskermolen, Susanne; van der Vorst, Maurice J D L; Becker-Commissaris, Annemarie; de van der Schueren, Marian A E; Buffart, Laurien M; Verheul, Henk M W

    2017-08-01

    Cancer-related fatigue (CRF) reduces quality of life and the activity level of patients with cancer. Cancer related fatigue can be reduced by exercise interventions that may concurrently increase muscle mass. We hypothesized that low muscle mass is directly related to higher CRF. A total of 233 patients with advanced cancer starting palliative chemotherapy for lung, colorectal, breast, or prostate cancer were studied. The skeletal muscle index (SMI) was calculated as the patient's muscle mass on level L3 or T4 of a computed tomography scan, adjusted for height. Fatigue was assessed with the Functional Assessment of Chronic Illness Therapy-fatigue questionnaire (cut-off for fatigue fatigue score was 36 (interquartile range 26-44). A higher SMI on level L3 was significantly associated with less CRF for men (B 0.447, P 0.004) but not for women (B - 0.401, P 0.090). No association between SMI on level T4 and the Functional Assessment of Chronic Illness Therapy-fatigue score was found (n = 82). The association between SMI and CRF may lead to the suggestion that male patients may be able to reduce fatigue by exercise interventions aiming at an increased muscle mass. In women with advanced cancer, CRF is more influenced by other causes, because it is not significantly related to muscle mass. To further reduce CRF in both men and women with cancer, multifactorial assessments need to be performed in order to develop effective treatment strategies. © 2017 The Authors. Journal of Cachexia, Sarcopenia and Muscle published by John Wiley & Sons Ltd on behalf of the Society on Sarcopenia, Cachexia and Wasting Disorders.

  16. Relative Skeletal Muscle Mass Is Associated with Development of Metabolic Syndrome

    Directory of Open Access Journals (Sweden)

    Byung Sam Park

    2013-12-01

    Full Text Available BackgroundVisceral adiposity is related to insulin resistance. Skeletal muscle plays a central role in insulin-mediated glucose disposal; however, little is known about the association between muscle mass and metabolic syndrome (MS. This study is to clarify the clinical role of skeletal muscle mass in development of MS.MethodsA total of 1,042 subjects were enrolled. Subjects with prior MS and chronic diseases were excluded. After 24 months, development of MS was assessed using NCEP-ATP III criteria. Skeletal muscle mass (SMM; kg, body fat mass (BFM; kg, and visceral fat area (VFA; cm2 were obtained from bioelectrical analysis. Then, the following values were calculated as follows: percent of SMM (SMM%; %: SMM (kg/weight (kg, skeletal muscle index (SMI; kg/m2: SMM (kg/height (m2, skeletal muscle to body fat ratio (MFR: SMM (kg/BFM (kg, and skeletal muscle to visceral fat ratio (SVR; kg/cm2: SMM (kg/VFA (cm2.ResultsAmong 838 subjects, 88 (10.5% were newly diagnosed with MS. Development of MS increased according to increasing quintiles of BMI, SMM, VFA, and SMI, but was negatively associated with SMM%, MFR, and SVR. VFA was positively associated with high waist circumference (WC, high blood pressure (BP, dysglycemia, and high triglyceride (TG. In contrast, MFR was negatively associated with high WC, high BP, dysglycemia, and high TG. SVR was negatively associated with all components of MS.ConclusionRelative SMM ratio to body composition, rather than absolute mass, may play a critical role in development of MS and could be used as a strong predictor.

  17. Stable walking with asymmetric legs

    International Nuclear Information System (INIS)

    Merker, Andreas; Rummel, Juergen; Seyfarth, Andre

    2011-01-01

    Asymmetric leg function is often an undesired side-effect in artificial legged systems and may reflect functional deficits or variations in the mechanical construction. It can also be found in legged locomotion in humans and animals such as after an accident or in specific gait patterns. So far, it is not clear to what extent differences in the leg function of contralateral limbs can be tolerated during walking or running. Here, we address this issue using a bipedal spring-mass model for simulating walking with compliant legs. With the help of the model, we show that considerable differences between contralateral legs can be tolerated and may even provide advantages to the robustness of the system dynamics. A better understanding of the mechanisms and potential benefits of asymmetric leg operation may help to guide the development of artificial limbs or the design novel therapeutic concepts and rehabilitation strategies.

  18. The automatic pelvic floor muscle response to the active straight leg raise in cases with pelvic girdle pain and matched controls.

    Science.gov (United States)

    Stuge, Britt; Sætre, Kaja; Ingeborg Hoff, Brækken

    2013-08-01

    The active straight leg raise (ASLR) test has been proposed as a clinical test for the assessment of pelvic girdle pain (PGP). Little is known about the activation of the pelvic floor muscles (PFM) during ASLR. The main aim of this study was to examine the automatic PFM contraction during ASLR. Specific aims were to compare automatic contraction to rest and to voluntary contraction, to compare PFM contraction during ASLR with and without compression and to examine whether there were any differences in PFM contraction between women with and without clinically diagnosed PGP during ASLR. Forty-nine pairs of women participated in a cross-sectional study with individual, one-to-one matched cases and controls. PFM was assessed by reliable and valid 3D ultrasound at rest, during voluntary and automatic contraction. Test-retest data for the levator hiatus during ASLR showed good repeatability. Significantly automatic PFM contractions occurred when ASLR tests were performed. There was a strong positive correlation between voluntary and automatic PFM contractions. Manual compression reduced the automatic PFM contraction during ASLR by 62-66%. There were no significant differences between cases and controls in reduction of levator hiatus or muscle length from rest to automatic contractions during ASLR. Interestingly, a significantly smaller levator hiatus was found in women with PGP than in controls, at rest, during an automatic contraction with ASLR and during voluntary contraction. In conclusion, a significant automatic PFM contraction occurred during ASLR, both in cases and in controls. Women with PGP had a significantly smaller levator hiatus than controls. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Improved skeletal muscle mass and strength after heavy strength training in very old individuals

    DEFF Research Database (Denmark)

    Bechshøft, Rasmus Leidesdorff; Malmgaard-Clausen, Nikolaj Mølkjær; Gliese, Bjørn

    2017-01-01

    . The increase in CSA is correlated inversely with the baseline level of CSA (R2 = 0.43, P strength, isokinetic peak torque and power increased significantly only in HRT by 10–15%, whereas knee extension one-repetition maximum (1 RM) improved by 91%. Physical functional tests......-training control group (CON). Both groups received similar protein supplementations. We studied 26 participants (86.9 ± 3.2 (SD) (83–94, range) years old) per-protocol. Quadriceps cross-sectional area (CSA) differed between groups at post-test (P ..., muscle fiber type distribution and size did not differ significantly between groups. We conclude that in protein supplemented very old individuals, heavy resistance training can increase muscle mass and strength, and that the relative improvement in mass is more pronounced when initial muscle mass is low....

  20. Artistic versus rhythmic gymnastics: effects on bone and muscle mass in young girls.

    Science.gov (United States)

    Vicente-Rodriguez, G; Dorado, C; Ara, I; Perez-Gomez, J; Olmedillas, H; Delgado-Guerra, S; Calbet, J A L

    2007-05-01

    We compared 35 prepubertal girls, 9 artistic gymnasts and 13 rhythmic gymnasts with 13 nonphysically active controls to study the effect of gymnastics on bone and muscle mass. Lean mass, bone mineral content and areal density were measured by dual energy X-ray absorptiometry, and physical fitness was also assessed. The artistic gymnasts showed a delay in pubertal development compared to the other groups (pgymnasts had a 16 and 17 % higher aerobic power and anaerobic capacity, while the rhythmic group had a 14 % higher anaerobic capacity than the controls, respectively (all pgymnasts had higher lean mass (prhythmic gymnasts and the controls. Body fat mass was 87.5 and 61.5 % higher in the controls than in the artistic and the rhythmic gymnasts (pgymnastic participation is associated with delayed pubertal development, enhanced physical fitness, muscle mass, and bone density in prepubertal girls, eliciting a higher osteogenic stimulus than rhythmic gymnastic.

  1. Within-Winter Flexibility in Muscle Masses, Myostatin, and Cellular Aerobic Metabolic Intensity in Passerine Birds.

    Science.gov (United States)

    Swanson, David L; King, Marisa O; Culver, William; Zhang, Yufeng

    Metabolic rates of passerine birds are flexible traits that vary both seasonally and among and within winters. Seasonal variation in summit metabolic rates (M sum = maximum thermoregulatory metabolism) in birds is consistently correlated with changes in pectoralis muscle and heart masses and sometimes with variation in cellular aerobic metabolic intensity, so these traits might also be associated with shorter-term, within-winter variation in metabolic rates. To determine whether these mechanisms are associated with within-winter variation in M sum , we examined the effects of short-term (ST; 0-7 d), medium-term (MT; 14-30 d), and long-term (LT; 30-yr means) temperature variables on pectoralis muscle and heart masses, pectoralis expression of the muscle-growth inhibitor myostatin and its metalloproteinase activators TLL-1 and TLL-2, and pectoralis and heart citrate synthase (CS; an indicator of cellular aerobic metabolic intensity) activities for two temperate-zone resident passerines, house sparrows (Passer domesticus) and dark-eyed juncos (Junco hyemalis). For both species, pectoralis mass residuals were positively correlated with ST temperature variables, suggesting that cold temperatures resulted in increased turnover of pectoralis muscle, but heart mass showed little within-winter variation for either species. Pectoralis mRNA and protein expression of myostatin and the TLLs were only weakly correlated with ST and MT temperature variables, which is largely consistent with trends in muscle masses for both species. Pectoralis and heart CS activities showed weak and variable trends with ST temperature variables in both species, suggesting only minor effects of temperature variation on cellular aerobic metabolic intensity. Thus, neither muscle or heart masses, regulation by the myostatin system, nor cellular aerobic metabolic intensity varied consistently with winter temperature, suggesting that other factors regulate within-winter metabolic variation in these birds.

  2. The Acute Effects of Unilateral Ankle Plantar Flexors Static- Stretching on Postural Sway and Gastrocnemius Muscle Activity During Single-Leg Balance Tasks

    Directory of Open Access Journals (Sweden)

    Bráulio N. Lima, Paulo R.G. Lucareli, Willy A. Gomes, Josinaldo J. Silva, Andre S. Bley, Erin H. Hartigan, Paulo H. Marchetti

    2014-09-01

    Full Text Available The aim of this study was to investigate the acute effects of unilateral ankle plantar flexors static- stretching on surface electromyography (sEMG and the center of pressure (COP during a single-leg balance task in both lower limbs. Fourteen young healthy, non-athletic individuals performed unipodal quiet standing for 30s before and after (stretched limb: immediately post-stretch, 10 and 20 minutes and non-stretched limb: immediately post-stretch a unilateral ankle plantar flexor static- stretching protocol [6 sets of 45s/15s, 70-90% point of discomfort (POD]. Postural sway was described using the COP area, COP speed (antero-posterior and medio-lateral directions and COP frequency (antero-posterior and medio-lateral directions. Surface EMG (EMG integral [IEMG] and Median frequency[FM] was used to describe the muscular activity of gastrocnemius lateralis. Ankle dorsiflexion passive range of motion increased in the stretched limb before and after the static-stretching protocol (mean ± SD: 15.0° ± 6.0 and 21.5° ± 7.0 [p < 0.001]. COP area and IEMG increased in the stretch limb between pre-stretching and immediately post-stretching (p = 0.015 and p = 0.036, respectively. In conclusion, our static- stretching protocol effectively increased passive ankle ROM. The increased ROM appears to increase postural sway and muscle activity; however these finding were only a temporary or transient effect.

  3. Does Skeletal Muscle Mass Influence Breast Cancer? Evaluating Mammary Tumorigenesis and Progression in Genetically Hyper-Muscular Mice

    National Research Council Canada - National Science Library

    Zimmers, Teresa

    2007-01-01

    .... To determine the role of increased skeletal muscle mass on breast cancer, the authors sought to measure rates of chemically induced mammary tumorigenesis and progression in genetically hypermuscular...

  4. Male sex, height, weight, and body mass index can increase external pressure to calf region using knee-crutch-type leg holder system in lithotomy position

    Directory of Open Access Journals (Sweden)

    Mizuno J

    2016-02-01

    Full Text Available Ju Mizuno,1 Toru Takahashi2 1Department of Anesthesiology and Pain Medicine, Juntendo University Faculty of Medicine, Bunkyo-ku, Tokyo, 2Faculty of Health and Welfare Science, Okayama Prefectural University, Soja-shi, Okayama, Japan Background: Well-leg compartment syndrome (WLCS is one of the catastrophic complications related to prolonged surgical procedures performed in the lithotomy position, using a knee-crutch-type leg holder (KCLH system, to support the popliteal fossae and calf regions. Obesity has been implicated as a risk factor in the lithotomy position-related WLCS during surgery. In the present study, we investigated the relationship between the external pressure (EP applied to the calf region using a KCLH system in the lithotomy position and selected physical characteristics. Methods: Twenty-one young, healthy volunteers (21.4±0.5 years of age, eleven males and ten females participated in this study. The KCLH system used was Knee Crutch®. We assessed four types of EPs applied to the calf region: box pressure, peak box pressure, contact pressure, and peak contact pressure, using pressure-distribution measurement system (BIG-MAT®. Relationships between these four EPs to the calf regions of both lower legs and a series of physical characteristics (sex, height, weight, and body mass index [BMI] were analyzed. Results: All four EPs applied to the bilateral calf regions were higher in males than in females. For all subjects, significant positive correlations were observed between all four EPs and height, weight, and BMI. Conclusion: EP applied to the calf region is higher in males than in females when the subject is supported by a KCLH system in the lithotomy position. In addition, EP increases with the increase in height, weight, and BMI. Therefore, male sex, height, weight, and BMI may contribute to the risk of inducing WLCS. Keywords: well-leg compartment syndrome, pressure-distribution measurement system, peak contact pressure

  5. Growth and the regulation of myotomal muscle mass in teleost fish.

    Science.gov (United States)

    Johnston, Ian A; Bower, Neil I; Macqueen, Daniel J

    2011-05-15

    Teleost muscle first arises in early embryonic life and its development is driven by molecules present in the egg yolk and modulated by environmental stimuli including temperature and oxygen. Several populations of myogenic precursor cells reside in the embryonic somite and external cell layer and contribute to muscle fibres in embryo, larval, juvenile and adult stages. Many signalling proteins and transcription factors essential for these events are known. In all cases, myogenesis involves myoblast proliferation, migration, fusion and terminal differentiation. Maturation of the embryonic muscle is associated with motor innervation and the development of a scaffold of connective tissue and complex myotomal architecture needed to generate swimming behaviour. Adult muscle is a heterogeneous tissue composed of several cell types that interact to affect growth patterns. The development of capillary and lymphatic circulations and extramuscular organs--notably the gastrointestinal, endocrine, neuroendocrine and immune systems--serves to increase information exchange between tissues and with the external environment, adding to the complexity of growth regulation. Teleosts often exhibit an indeterminate growth pattern, with body size and muscle mass increasing until mortality or senescence occurs. The dramatic increase in myotomal muscle mass between embryo and adult requires the continuous production of muscle fibres until 40-50% of the maximum body length is reached. Sarcomeric proteins can be mobilised as a source of amino acids for energy metabolism by other tissues and for gonad generation, requiring the dynamic regulation of muscle mass throughout the life cycle. The metabolic and contractile phenotypes of muscle fibres also show significant plasticity with respect to environmental conditions, migration and spawning. Many genes regulating muscle growth are found as multiple copies as a result of paralogue retention following whole-genome duplication events in teleost

  6. Counteracting age-related loss of skeletal muscle mass

    DEFF Research Database (Denmark)

    Bechshøft, Rasmus; Reitelseder, Søren; Højfeldt, Grith

    2016-01-01

    Mass (CALM) to investigate the impact of lifestyle changes on physical and functional outcomes as well as everyday practices and habits in a qualitative context. Methods We will randomize 205 participants older than 65 years to be given 1 year of two daily nutrient supplements with 10 g of sucrose...

  7. Intermittent stretch training of rabbit plantarflexor muscles increases soleus mass and serial sarcomere number.

    Science.gov (United States)

    De Jaeger, Dominique; Joumaa, Venus; Herzog, Walter

    2015-06-15

    In humans, enhanced joint range of motion is observed after static stretch training and results either from an increased stretch tolerance or from a change in the biomechanical properties of the muscle-tendon unit. We investigated the effects of an intermittent stretch training on muscle biomechanical and structural variables. The left plantarflexors muscles of seven anesthetized New Zealand (NZ) White rabbits were passively and statically stretched three times a week for 4 wk, while the corresponding right muscles were used as nonstretched contralateral controls. Before and after the stretching protocol, passive torque produced by the left plantarflexor muscles as a function of the ankle angle was measured. The left and right plantarflexor muscles were harvested from dead rabbits and used to quantify possible changes in muscle structure. Significant mass and serial sarcomere number increases were observed in the stretched soleus but not in the plantaris or medial gastrocnemius. This difference in adaptation between the plantarflexors is thought to be the result of their different fiber type composition and pennation angles. Neither titin isoform nor collagen amount was modified in the stretched compared with the control soleus muscle. Passive torque developed during ankle dorsiflexion was not modified after the stretch training on average, but was decreased in five of the seven experimental rabbits. Thus, an intermittent stretching program similar to those used in humans can produce a change in the muscle structure of NZ White rabbits, which was associated in some rabbits with a change in the biomechanical properties of the muscle-tendon unit. Copyright © 2015 the American Physiological Society.

  8. Leg Swelling

    Science.gov (United States)

    ... ed. New York, N.Y.: The McGraw Hill Companies; 2016. http://www.accessmedicine.com. Accessed Dec. 31, ... http://www.mayoclinic.org/symptoms/leg-swelling/basics/definition/SYM-20050910 . Mayo Clinic Footer Legal Conditions and ...

  9. Pathobiochemical Changes in Diabetic Skeletal Muscle as Revealed by Mass-Spectrometry-Based Proteomics

    Directory of Open Access Journals (Sweden)

    Kay Ohlendieck

    2012-01-01

    Full Text Available Insulin resistance in skeletal muscle tissues and diabetes-related muscle weakness are serious pathophysiological problems of increasing medical importance. In order to determine global changes in the protein complement of contractile tissues due to diabetes mellitus, mass-spectrometry-based proteomics has been applied to the investigation of diabetic muscle. This review summarizes the findings from recent proteomic surveys of muscle preparations from patients and established animal models of type 2 diabetes. The potential impact of novel biomarkers of diabetes, such as metabolic enzymes and molecular chaperones, is critically examined. Disease-specific signature molecules may be useful for increasing our understanding of the molecular and cellular mechanisms of insulin resistance and possibly identify new therapeutic options that counteract diabetic abnormalities in peripheral organ systems. Importantly, the biomedical establishment of biomarkers promises to accelerate the development of improved diagnostic procedures for characterizing individual stages of diabetic disease progression, including the early detection of prediabetic complications.

  10. Influence of amino acids, dietary protein, and physical activity on muscle mass development in humans

    DEFF Research Database (Denmark)

    Dideriksen, Kasper; Reitelseder, Søren; Holm, Lars

    2013-01-01

    Ingestion of protein is crucial for maintenance of a variety of body functions and within the scope of this review we will specifically focus on the regulation of skeletal muscle mass. A quantitative limitation exists as to how much muscle protein the body can synthesize in response to protein...... intake. Ingestion of excess protein exerts an unwanted load to the body and therefore, it is important to find the least amount of protein that provides the maximal hypertrophic stimulus. Hence, research has focused on revealing the relationship between protein intake (dose) and its resulting stimulation...... of muscle protein synthesis (response). In addition to the protein amount, the protein digestibility and, hence, the availability of its constituent amino acids is decisive for the response. In this regard, recent studies have provided in-depth knowledge about the time-course of the muscle protein synthetic...

  11. Role of Protein Carbonylation in Skeletal Muscle Mass Loss Associated with Chronic Conditions

    Directory of Open Access Journals (Sweden)

    Esther Barreiro

    2016-05-01

    Full Text Available Muscle dysfunction, characterized by a reductive remodeling of muscle fibers, is a common systemic manifestation in highly prevalent conditions such as chronic heart failure (CHF, chronic obstructive pulmonary disease (COPD, cancer cachexia, and critically ill patients. Skeletal muscle dysfunction and impaired muscle mass may predict morbidity and mortality in patients with chronic diseases, regardless of the underlying condition. High levels of oxidants may alter function and structure of key cellular molecules such as proteins, DNA, and lipids, leading to cellular injury and death. Protein oxidation including protein carbonylation was demonstrated to modify enzyme activity and DNA binding of transcription factors, while also rendering proteins more prone to proteolytic degradation. Given the relevance of protein oxidation in the pathophysiology of many chronic conditions and their comorbidities, the current review focuses on the analysis of different studies in which the biological and clinical significance of the modifications induced by reactive carbonyls on proteins have been explored so far in skeletal muscles of patients and animal models of chronic conditions such as COPD, disuse muscle atrophy, cancer cachexia, sepsis, and physiological aging. Future research will elucidate the specific impact and sites of reactive carbonyls on muscle protein content and function in human conditions.

  12. Role of Protein Carbonylation in Skeletal Muscle Mass Loss Associated with Chronic Conditions.

    Science.gov (United States)

    Barreiro, Esther

    2016-05-06

    Muscle dysfunction, characterized by a reductive remodeling of muscle fibers, is a common systemic manifestation in highly prevalent conditions such as chronic heart failure (CHF), chronic obstructive pulmonary disease (COPD), cancer cachexia, and critically ill patients. Skeletal muscle dysfunction and impaired muscle mass may predict morbidity and mortality in patients with chronic diseases, regardless of the underlying condition. High levels of oxidants may alter function and structure of key cellular molecules such as proteins, DNA, and lipids, leading to cellular injury and death. Protein oxidation including protein carbonylation was demonstrated to modify enzyme activity and DNA binding of transcription factors, while also rendering proteins more prone to proteolytic degradation. Given the relevance of protein oxidation in the pathophysiology of many chronic conditions and their comorbidities, the current review focuses on the analysis of different studies in which the biological and clinical significance of the modifications induced by reactive carbonyls on proteins have been explored so far in skeletal muscles of patients and animal models of chronic conditions such as COPD, disuse muscle atrophy, cancer cachexia, sepsis, and physiological aging. Future research will elucidate the specific impact and sites of reactive carbonyls on muscle protein content and function in human conditions.

  13. Specific protein changes contribute to the differential muscle mass loss during ageing.

    Science.gov (United States)

    Capitanio, Daniele; Vasso, Michele; De Palma, Sara; Fania, Chiara; Torretta, Enrica; Cammarata, Francesco P; Magnaghi, Valerio; Procacci, Patrizia; Gelfi, Cecilia

    2016-02-01

    In the skeletal muscle, the ageing process is characterized by a loss of muscle mass and strength, coupled with a decline of mitochondrial function and a decrease of satellite cells. This profile is more pronounced in hindlimb than in forelimb muscles, both in humans and in rodents. Utilizing light and electron microscopy, myosin heavy chain isoform distribution, proteomic analysis by 2D-DIGE, MALDI-TOF MS and quantitative immunoblotting, this study analyzes the protein levels and the nuclear localization of specific molecules, which can contribute to a preferential muscle loss. Our results identify the molecular changes in the hindlimb (gastrocnemius) and forelimb (triceps) muscles during ageing in rats (3- and 22-month-old). Specifically, the oxidative metabolism contributes to tissue homeostasis in triceps, whereas respiratory chain disruption and oxidative-stress-induced damage imbalance the homeostasis in gastrocnemius muscle. High levels of dihydrolipoyllysine-residue acetyltransferase (Dlat) and ATP synthase subunit alpha (Atp5a1) are detected in triceps and gastrocnemius, respectively. Interestingly, in triceps, both molecules are increased in the nucleus in aged rats and are associated to an increased protein acetylation and myoglobin availability. Furthermore, autophagy is retained in triceps whereas an enhanced fusion, decrement of mitophagy and of regenerative potential is observed in aged gastrocnemius muscle. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Ultrasound assessment of lower limb muscle mass in response to resistance training in COPD

    Directory of Open Access Journals (Sweden)

    Menon Manoj K

    2012-12-01

    Full Text Available Abstract Background Quantifying the improvements in lower limb or quadriceps muscle mass following resistance training (RT, is an important outcome measure in COPD. Ultrasound is a portable, radiation free imaging technique that can measure the size of superficial muscles belonging to the quadriceps group such as the rectus femoris, but has not been previously used in COPD patients following RT. We compared the responsiveness of ultrasound derived measures of quadriceps mass against dual energy x-ray absorptiometry (DEXA, in patients with COPD and healthy controls following a programme of high intensity knee extensor RT. Methods Portable ultrasound was used to assess the size of the dominant quadriceps in 45 COPD patients and 19 healthy controls-before, during, and after 8 weeks of bilateral high intensity isokinetic knee extensor RT. Scanning was performed at the mid-thigh region, and 2 indices of quadriceps mass were measured-rectus femoris cross-sectional area (RFcsa and quadriceps muscle thickness (Qt. Thigh lean mass (Tdexa was determined by DEXA. Results Training resulted in a significant increase in Tdexa, RFcsa and Qt in COPD patients [5.7%, 21.8%, 12.1% respectively] and healthy controls [5.4%, 19.5%, 10.9 respectively]. The effect size for the changes in RFcsa (COPD= 0.77; Healthy=0.83 and Qt (COPD=0.36; Healthy=0.78 were greater than the changes in Tdexa (COPD=0.19; Healthy=0.26 following RT. Conclusions Serial ultrasound measurements of the quadriceps can detect changes in muscle mass in response to RT in COPD. The technique has good reproducibility, and may be more sensitive to changes in muscle mass when compared to DEXA. Trial registration http://www.controlled-trials.com (Identifier: ISRCTN22764439

  15. Growth hormone mitigates loss of periosteal bone formation and muscle mass in disuse osteopenic rats

    DEFF Research Database (Denmark)

    Grubbe, M-C; Thomsen, Jesper Skovhus; Nyengaard, J R

    2014-01-01

    Growth hormone (GH) is a potent anabolic agent capable of increasing both bone and muscle mass. The aim was to investigate whether GH could counteract disuse-induced loss of bone and muscle mass in a rat model. Paralysis was induced by injecting 4 IU Botox (BTX) into the muscles of the right hind...... limb. Sixty female Wistar rats, 14 weeks old, were divided into the following groups: baseline, controls, BTX, BTX+GH, and GH. GH was given at a dosage of 5 mg/kg/d for 4 weeks. Compared with controls, BTX resulted in lower periosteal bone formation rate (BFR/BS,-79%, Pbone mineral density (a......BMD, -13%, Pbone volume (BV/TV, -26%, Pbone strength (-12%, P

  16. Premature loss of muscle mass and function in type 2 diabetes.

    Science.gov (United States)

    Guerrero, N; Bunout, D; Hirsch, S; Barrera, G; Leiva, L; Henríquez, S; De la Maza, M P

    2016-07-01

    Muscle mass and function are among the most relevant factors that contribute to an optimal quality of life, and are strong predictors of mortality in the elderly. Loss of lean tissues and deterioration of muscle function have been described as one of the many complications of type 2 diabetes mellitus (DM2), but most studies do not isolate age as an intervening factor. To study whether adult DM2 patients up to 60years of age have decreased muscle mass and function compared with healthy non-diabetic (ND) subjects of similar age. Appendicular fat-free mass (ApFFM) by dual X-ray absorptiometry (DEXA), handgrip strength (HS), quadriceps strength (QS), 12 min walking capacity (12MW) and the Timed Up and Go test (TUG) were measured in 100 DM2 patients and 39 ND controls. Muscle quality, or the ratio between lean mass and muscle strength of upper and lower limbs, and the functional limitations associated with pain and stiffness assessed according to the Western Ontario and McMaster Universities Arthrosis Index (WOMAC) were also recorded. Specific tests were performed to rule out microvascular diabetic complications (retinal and peripheral nerves), metabolic control, kidney function and vitamin D status and examine their association with ApFFM and function. ApFFM was significantly higher among DM2 female patients and lower among diabetic men. However opposite results were obtained when individual values were corrected for body mass index (BMI), specifically among women, who were more likely to be obese. As for muscle strength and global functionality tests, significantly better performances in TUG, 12MW, QS and HS were observed among ND subjects of both sexes. These differences prevailed even after excluding diabetic patients with microvascular complications as well as those with more than 10years of diabetes. Muscle quality was also significantly better among ND women. Higher scores of pain and stiffness in the WOMAC scale correlated with 12MW and TUG in both groups but

  17. Tissue Selective Androgen Receptor Modulators (SARMs) Increase Pelvic Floor Muscle Mass in Ovariectomized Mice.

    Science.gov (United States)

    Ponnusamy, Suriyan; Sullivan, Ryan D; Thiyagarajan, Thirumagal; Tillmann, Heather; Getzenberg, Robert H; Narayanan, Ramesh

    2017-03-01

    Stress urinary incontinence (SUI), a prevalent condition, is represented by an involuntary leakage of urine that results, at least in part, from weakened or damaged pelvic floor muscles and is triggered by physical stress. Current treatment options are limited with no oral therapies available. The pelvic floor is rich in androgen receptor and molecules with anabolic activity including selective androgen receptor modulators (SARMs) may serve as therapeutic options for individuals with SUI. In this study, two SARMs (GTx-024 and GTx-027) were evaluated in a post-menopausal animal model in order to determine their effect on pelvic floor muscles. Female C57BL/6 mice were ovariectomized and their pelvic muscles allowed to regress. The animals were then treated with vehicle or doses of GTx-024 or GTx-027. Animal total body weight, lean body mass, and pelvic floor muscle weights were measured along with the expression of genes associated with muscle catabolism. Treatment with the SARMs resulted in a restoration of the pelvic muscles to the sham-operated weight. Coordinately, the induction of genes associated with muscle catabolism was inhibited. Although a trend was observed towards an increase in total lean body mass in the SARM-treated groups, no significant differences were detected. Treatment of an ovariectomized mouse model with SARMs resulted in an increase in pelvic floor muscles, which may translate to an improvement of symptoms associated with SUI and serves as the basis for evaluating their clinical use. J. Cell. Biochem. 118: 640-646, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  18. Sarcopenia and liver transplant: The relevance of too little muscle mass

    Science.gov (United States)

    Kallwitz, Eric R

    2015-01-01

    Loss of muscle mass and function is a common occurrence in both patients with decompensated cirrhosis and those undergoing liver transplantation. Sarcopenia is associated with morbidity and mortality before and after liver transplantation. The ability of skeletal muscle mass to recover after transplant is questionable, and long term adverse events associated with persistent sarcopenia have not been well studied. Limited data is available examining mechanisms by which decreased muscle mass might develop. It is not clear which interventions might reduce the prevalence of sarcopenia and associated health burdens. However, measures to either decrease portal hypertension or improve nutrition appear to have benefit. Research on sarcopenia in the liver transplant setting is hampered by differing methodology to quantify muscle mass and varied thresholds determining the presence of sarcopenia. One area highlighted in this review is the heterogeneity used when defining sarcopenia. The health consequences, clinical course and potential pathophysiologic mechanisms of sarcopenia in the setting of cirrhosis and liver transplantation are further discussed. PMID:26494955

  19. The effects of dietary protein intake on appendicular lean mass and muscle function in elderly men

    DEFF Research Database (Denmark)

    Mitchell, Cameron J; Milan, Amber M; Mitchell, Sarah M

    2017-01-01

    Background: The Recommended Daily Allowance (RDA) for protein intake in the adult population is widely promoted as 0.8 g · kg-1 · d-1 Aging may increase protein requirements, particularly to maintain muscle mass.Objective: We investigated whether controlled protein consumption at the current RDA ...

  20. MUSCLE MASS HYPERTROPHY EXERCISES WITH PROGRESSIVE WEIGHTING, AND IT’S VARIATIONS

    OpenAIRE

    Valentin CRISTIAN

    2013-01-01

    The main purpose of any athlete working out in a gym is to increase the muscular mass. In order to reach this objective there is a must to induce some chemical reactions in skeleton muscles, as a reply to physiological fatigue. The final effect consists in muscular hypertrophy.

  1. Strength Exercise Improves Muscle Mass and Hepatic Insulin Sensitivity in Obese Youth

    NARCIS (Netherlands)

    Van Der Heijden, Gert-Jan; Wang, Zhiyue J.; Chu, Zili; Toffolo, Gianna; Manesso, Erica; Sauer, Pieter J. J.; Sunehag, Agneta L.

    2010-01-01

    VAN DER HEIJDEN, G.-J., Z. J. WANG, Z. CHU, G. TOFFOLO, E. MANESSO, P. J. J. SAUER, and A. L. SUNEHAG. Strength Exercise Improves Muscle Mass and Hepatic Insulin Sensitivity in Obese Youth. Med. Sci. Sports Exerc., Vol. 42, No. 11, pp. 1973-1980, 2010. Introduction: Data on the metabolic effects of

  2. Postoperative loss of skeletal muscle mass, complications and quality of life in patients undergoing cardiac surgery

    NARCIS (Netherlands)

    van Venrooij, Lenny M. W.; Verberne, Hein J.; de Vos, Rien; Borgmeijer-Hoelen, Mieke M. M. J.; van Leeuwen, Paul A. M.; de Mol, Bas A. J. M.

    2012-01-01

    Objective: The objective of this study was to describe postoperative undernutrition in terms of postoperative losses of appendicular skeletal muscle mass (ASMM) with respect to complications, quality of life, readmission, and 1-y mortality after cardiac surgery. Methods: Patients undergoing cardiac

  3. Middle cerebral artery blood velocity depends on cardiac output during exercise with a large muscle mass

    NARCIS (Netherlands)

    Ide, K.; Pott, F.; van Lieshout, J. J.; Secher, N. H.

    1998-01-01

    We tested the hypothesis that pharmacological reduction of the increase in cardiac output during dynamic exercise with a large muscle mass would influence the cerebral blood velocity/perfusion. We studied the relationship between changes in cerebral blood velocity (transcranial Doppler), rectus

  4. Improved skeletal muscle mass and strength after heavy strength training in very old individuals.

    Science.gov (United States)

    Bechshøft, Rasmus Leidesdorff; Malmgaard-Clausen, Nikolaj Mølkjær; Gliese, Bjørn; Beyer, Nina; Mackey, Abigail L; Andersen, Jesper Løvind; Kjær, Michael; Holm, Lars

    2017-06-01

    Age-related loss of muscle mass and function represents personal and socioeconomic challenges. The purpose of this study was to determine the adaptation of skeletal musculature in very old individuals (83+ years) performing 12weeks of heavy resistance training (3×/week) (HRT) compared to a non-training control group (CON). Both groups received similar protein supplementations. We studied 26 participants (86.9±3.2 (SD) (83-94, range) years old) per-protocol. Quadriceps cross-sectional area (CSA) differed between groups at post-test (Pmuscle isometric strength, isokinetic peak torque and power increased significantly only in HRT by 10-15%, whereas knee extension one-repetition maximum (1 RM) improved by 91%. Physical functional tests, muscle fiber type distribution and size did not differ significantly between groups. We conclude that in protein supplemented very old individuals, heavy resistance training can increase muscle mass and strength, and that the relative improvement in mass is more pronounced when initial muscle mass is low. Copyright © 2017. Published by Elsevier Inc.

  5. Effect of small-sided team sport training and protein intake on muscle mass, physical function and markers of health in older untrained adults: A randomized trial

    Science.gov (United States)

    Pedersen, Mogens Theisen; Brahe, Lena Kirchner; Melcher, Pia Sandfeld; Alstrøm, Joachim Meno; Bangsbo, Jens

    2017-01-01

    The effect of small-sided team sport training and protein intake on muscle mass, physical function, and adaptations important for health in untrained older adults was examined. Forty-eight untrained older (72±6 (±standard deviation, SD) years men and women were divided into either a team sport group ingesting a drink high in protein (18 g) immediately and 3 h after each training session (TS-HP, n = 13), a team sport group ingesting an isocaloric drink with low protein content (3 g; TS-LP, n = 18), or a control group continuing their normal activities (CON, n = 17). The team sport training was performed as ~20 min of small-sided ball games twice a week over 12 weeks. After the intervention period, leg muscle mass was 0.6 kg higher (P = 0.047) in TS-HP, with no effect in TS-LP. In TS-HP, number of sit-to-stand repetitions increased (1.2±0.6, P = 0.054), time to perform 2.45 m up-and-go was lower (0.7±0.3 s, P = 0.03) and number of arm curl repetitions increased (3.5±1.2, P = 0.01), whereas in TS-LP only number of repetitions in sit-to-stand was higher (1.6±0.6, P = 0.01). In TS-LP, reductions were observed in total and abdominal fat mass (1.2±0.5 and 0.4±0.2 kg, P = 0.03 and P = 0.02, respectively), heart rate at rest (9±3 bpm, P = 0.002) and plasma C-reactive protein (1.8±0.8 mmol/L, P = 0.03), with no effects in TS-HP. Thus, team sport training improves functional capacity of untrained older adults and increases leg muscle mass only when ingesting proteins after training. Furthermore, team sport training followed by intake of drink with low protein content does lower fat mass, heart rate at rest and level of systemic inflammation. Trial Registration: clinicaltrials.gov NCT03120143 PMID:29016675

  6. Effect of small-sided team sport training and protein intake on muscle mass, physical function and markers of health in older untrained adults: A randomized trial.

    Science.gov (United States)

    Vorup, Jacob; Pedersen, Mogens Theisen; Brahe, Lena Kirchner; Melcher, Pia Sandfeld; Alstrøm, Joachim Meno; Bangsbo, Jens

    2017-01-01

    The effect of small-sided team sport training and protein intake on muscle mass, physical function, and adaptations important for health in untrained older adults was examined. Forty-eight untrained older (72±6 (±standard deviation, SD) years men and women were divided into either a team sport group ingesting a drink high in protein (18 g) immediately and 3 h after each training session (TS-HP, n = 13), a team sport group ingesting an isocaloric drink with low protein content (3 g; TS-LP, n = 18), or a control group continuing their normal activities (CON, n = 17). The team sport training was performed as ~20 min of small-sided ball games twice a week over 12 weeks. After the intervention period, leg muscle mass was 0.6 kg higher (P = 0.047) in TS-HP, with no effect in TS-LP. In TS-HP, number of sit-to-stand repetitions increased (1.2±0.6, P = 0.054), time to perform 2.45 m up-and-go was lower (0.7±0.3 s, P = 0.03) and number of arm curl repetitions increased (3.5±1.2, P = 0.01), whereas in TS-LP only number of repetitions in sit-to-stand was higher (1.6±0.6, P = 0.01). In TS-LP, reductions were observed in total and abdominal fat mass (1.2±0.5 and 0.4±0.2 kg, P = 0.03 and P = 0.02, respectively), heart rate at rest (9±3 bpm, P = 0.002) and plasma C-reactive protein (1.8±0.8 mmol/L, P = 0.03), with no effects in TS-HP. Thus, team sport training improves functional capacity of untrained older adults and increases leg muscle mass only when ingesting proteins after training. Furthermore, team sport training followed by intake of drink with low protein content does lower fat mass, heart rate at rest and level of systemic inflammation. clinicaltrials.gov NCT03120143.

  7. Strength, but not muscle mass, is associated with mortality in the health, aging and body composition study cohort

    NARCIS (Netherlands)

    Newman, Anne B; Kupelian, Varant; Visser, Marjolein; Simonsick, Eleanor M; Goodpaster, Bret H; Kritchevsky, Stephen B; Tylavsky, Frances A; Rubin, Susan M; Harris, Tamara B

    BACKGROUND: Although muscle strength and mass are highly correlated, the relationship between direct measures of low muscle mass (sarcopenia) and strength in association with mortality has not been examined. METHODS: Total mortality rates were examined in the Health, Aging and Body Composition

  8. Signalling pathways regulating muscle mass in ageing skeletal muscle. The role of the IGF1-Akt-mTOR-FoxO pathway

    NARCIS (Netherlands)

    Sandri, M.; Barberi, L.; Bijlsma, A.Y.; Blaauw, B.; Dyar, K.A.; Milan, G.; Mammucari, C.; Meskers, C.G.M.; Pallafacchina, G.; Paoli, A.; Pion, D.; Roceri, M.; Romanello, V.; Serrano, A.L.; Toniolo, L.; Larsson, L.; Maier, A.B.; Munoz-Canoves, P.; Musaro, A.; Pende, M.; Reggiani, C.; Rizzuto, R.; Schiaffino, S.

    2013-01-01

    During ageing skeletal muscles undergo a process of structural and functional remodelling that leads to sarcopenia, a syndrome characterized by loss of muscle mass and force and a major cause of physical frailty. To determine the causes of sarcopenia and identify potential targets for interventions

  9. Leg Problems

    Science.gov (United States)

    ... TEAR of the ACHILLES TENDON that attaches the calf muscle to the heel. This injury will cause pain and difficulty pointing the foot down. A TORN CALF MUSCLE will be painful and might produce bruises. Self ...

  10. Leg pain

    Science.gov (United States)

    ... to a muscle cramp (also called a charley horse ). Common causes of cramps include: Dehydration or low ... muscle ( strain ) Hairline crack in the bone (stress fracture) Inflamed tendon ( tendinitis ) Shin splints (pain in the ...

  11. Effect of Leg Dominance on The Center-of-Mass Kinematics During an Inside-of-the-Foot Kick in Amateur Soccer Players

    Directory of Open Access Journals (Sweden)

    Zago Matteo

    2014-10-01

    Full Text Available Soccer kicking kinematics has received wide interest in literature. However, while the instep-kick has been broadly studied, only few researchers investigated the inside-of-the-foot kick, which is one of the most frequently performed techniques during games. In particular, little knowledge is available about differences in kinematics when kicking with the preferred and non-preferred leg. A motion analysis system recorded the three-dimensional coordinates of reflective markers placed upon the body of nine amateur soccer players (23.0 ± 2.1 years, BMI 22.2 ± 2.6 kg/m2, who performed 30 pass-kicks each, 15 with the preferred and 15 with the non-preferred leg. We investigated skill kinematics while maintaining a perspective on the complete picture of movement, looking for laterality related differences. The main focus was laid on: anatomical angles, contribution of upper limbs in kick biomechanics, kinematics of the body Center of Mass (CoM, which describes the whole body movement and is related to balance and stability. When kicking with the preferred leg, CoM displacement during the ground-support phase was 13% higher (p<0.001, normalized CoM height was 1.3% lower (p<0.001 and CoM velocity 10% higher (p<0.01; foot and shank velocities were about 5% higher (p<0.01; arms were more abducted (p<0.01; shoulders were rotated more towards the target (p<0.01, 6° mean orientation difference.

  12. Male sex, height, weight, and body mass index can increase external pressure to calf region using knee-crutch-type leg holder system in lithotomy position.

    Science.gov (United States)

    Mizuno, Ju; Takahashi, Toru

    2016-01-01

    Well-leg compartment syndrome (WLCS) is one of the catastrophic complications related to prolonged surgical procedures performed in the lithotomy position, using a knee-crutch-type leg holder (KCLH) system, to support the popliteal fossae and calf regions. Obesity has been implicated as a risk factor in the lithotomy position-related WLCS during surgery. In the present study, we investigated the relationship between the external pressure (EP) applied to the calf region using a KCLH system in the lithotomy position and selected physical characteristics. Twenty-one young, healthy volunteers (21.4±0.5 years of age, eleven males and ten females) participated in this study. The KCLH system used was Knee Crutch(®). We assessed four types of EPs applied to the calf region: box pressure, peak box pressure, contact pressure, and peak contact pressure, using pressure-distribution measurement system (BIG-MAT(®)). Relationships between these four EPs to the calf regions of both lower legs and a series of physical characteristics (sex, height, weight, and body mass index [BMI]) were analyzed. All four EPs applied to the bilateral calf regions were higher in males than in females. For all subjects, significant positive correlations were observed between all four EPs and height, weight, and BMI. EP applied to the calf region is higher in males than in females when the subject is supported by a KCLH system in the lithotomy position. In addition, EP increases with the increase in height, weight, and BMI. Therefore, male sex, height, weight, and BMI may contribute to the risk of inducing WLCS.

  13. Testosterone therapy preserves muscle strength and power in aging men with type 2 diabete

    DEFF Research Database (Denmark)

    Magnussen, L V; Hvid, L G; Hermann, A P

    2017-01-01

    The purpose of the study was to evaluate whether testosterone replacement therapy improves muscle mechanical and physical function in addition to increasing lean leg mass and total lean body mass in aging men with type 2 diabetes and lowered bio-available testosterone (BioT) levels. Thirty-nine men...... function was assessed by Nottingham Leg Rig (leg extension power) and isokinetic dynamometry (knee extensor maximal isometric contraction, rate of force development (RFD100), maximal dynamic contraction (Dyn180)). Physical function was assessed by gait speed. Body composition was assessed by whole body...... aged 50-70 years with type 2 diabetes and BioT levels Muscle mechanical...

  14. Testosterone therapy preserves muscle strength and power in aging men with type 2 diabete

    DEFF Research Database (Denmark)

    Magnussen, L V; Hvid, L G; Hermann, A P

    2017-01-01

    The purpose of the study was to evaluate whether testosterone replacement therapy improves muscle mechanical and physical function in addition to increasing lean leg mass and total lean body mass in aging men with type 2 diabetes and lowered bio-available testosterone (BioT) levels. Thirty-nine men...... aged 50-70 years with type 2 diabetes and BioT levels Muscle mechanical...... function was assessed by Nottingham Leg Rig (leg extension power) and isokinetic dynamometry (knee extensor maximal isometric contraction, rate of force development (RFD100), maximal dynamic contraction (Dyn180)). Physical function was assessed by gait speed. Body composition was assessed by whole body...

  15. Muscle mass, BMI, and mortality among adults in the United States: A population-based cohort study.

    Science.gov (United States)

    Abramowitz, Matthew K; Hall, Charles B; Amodu, Afolarin; Sharma, Deep; Androga, Lagu; Hawkins, Meredith

    2018-01-01

    The level of body-mass index (BMI) associated with the lowest risk of death remains unclear. Although differences in muscle mass limit the utility of BMI as a measure of adiposity, no study has directly examined the effect of muscle mass on the BMI-mortality relationship. Body composition was measured by dual-energy x-ray absorptiometry in 11,687 participants of the National Health and Nutrition Examination Survey 1999-2004. Low muscle mass was defined using sex-specific thresholds of the appendicular skeletal muscle mass index (ASMI). Proportional hazards models were created to model associations with all-cause mortality. At any level of BMI ≥22, participants with low muscle mass had higher body fat percentage (%TBF), an increased likelihood of diabetes, and higher adjusted mortality than other participants. Increases in %TBF manifested as 30-40% smaller changes in BMI than were observed in participants with preserved muscle mass. Excluding participants with low muscle mass or adjustment for ASMI attenuated the risk associated with low BMI, magnified the risk associated with high BMI, and shifted downward the level of BMI associated with the lowest risk of death. Higher ASMI was independently associated with lower mortality. Effects were similar in never-smokers and ever-smokers. Additional adjustment for waist circumference eliminated the risk associated with higher BMI. Results were unchanged after excluding unintentional weight loss, chronic illness, early mortality, and participants performing muscle-strengthening exercises or recommended levels of physical activity. Muscle mass mediates associations of BMI with adiposity and mortality and is inversely associated with the risk of death. After accounting for muscle mass, the BMI associated with the greatest survival shifts downward toward the normal range. These results provide a concrete explanation for the obesity paradox.

  16. Calf circumference as a surrogate marker of muscle mass for diagnosing sarcopenia in Japanese men and women.

    Science.gov (United States)

    Kawakami, Ryoko; Murakami, Haruka; Sanada, Kiyoshi; Tanaka, Noriko; Sawada, Susumu S; Tabata, Izumi; Higuchi, Mitsuru; Miyachi, Motohiko

    2015-08-01

    To examine the relationship between calf circumference and muscle mass, and to evaluate the suitability of calf circumference as a surrogate marker of muscle mass for the diagnosis of sarcopenia among middle-aged and older Japanese men and women. A total of 526 adults aged 40-89 years participated in the present cross-sectional study. The maximum calf circumference was measured in a standing position. Appendicular skeletal muscle mass was measured using dual-energy X-ray absorptiometry, and the skeletal muscle index was calculated as appendicular skeletal muscle mass divided by the square of the height (kg/m(2)). The cut-off values for sarcopenia were defined as a skeletal muscle index of less than -2 standard deviations of the mean value for Japanese young adults, as defined previously. Calf circumference was positively correlated with appendicular skeletal muscle (r = 0.81 in men, r = 0.73 in women) and skeletal muscle index (r = 0.80 in men, r = 0.69 in women). In receiver operating characteristic analysis, the optimal calf circumference cut-off values for predicting sarcopenia were 34 cm (sensitivity 88%, specificity 91%) in men and 33 cm (sensitivity 76%, specificity 73%) in women. Calf circumference was positively correlated with appendicular skeletal muscle mass and skeletal muscle index, and could be used as a surrogate marker of muscle mass for diagnosing sarcopenia. The suggested cut-off values of calf circumference for predicting low muscle mass are <34 cm in men and <33 cm in women. © 2014 Japan Geriatrics Society.

  17. Active and Inactive Leg Hemodynamics during Sequential Single-Leg Interval Cycling.

    Science.gov (United States)

    Gordon, Nicole; Abbiss, Chris R; Ihsan, Mohammed; Maiorana, Andrew J; Peiffer, Jeremiah J

    2018-01-11

    Leg order during sequential single-leg cycling (i.e. exercising both legs independently within a single session) may affect local muscular responses potentially influencing adaptations. This study examined the cardiovascular and skeletal muscle hemodynamic responses during double-leg and sequential single-leg cycling. Ten young healthy adults (28 ± 6 y) completed six 1-min double-leg intervals interspersed with one minute of passive recovery and, on a separate occasion, 12 (six with one leg followed by six with the other leg) 1-min single-leg intervals interspersed with one minute of passive recovery. Oxygen consumption, heart rate, blood pressure, muscle oxygenation, muscle blood volume and power output were measured throughout each session. Oxygen consumption, heart rate and power output were not different between sets of single-leg intervals but the average of both sets was lower than the double-leg intervals. Mean arterial pressure was higher during double-leg compared with sequential single-leg intervals (115 ± 9 mmHg vs. 104 ± 9 mmHg; p<0.05) and higher during the initial compared with second set of single-leg intervals (108 ± 10 mmHg vs. 101 ± 10 mmHg; p<0.05). The increase in muscle blood volume from baseline was similar between the active single-leg and double-leg (267 ± 150 μM[BULLET OPERATOR]cm vs. 214 ± 169 μM[BULLET OPERATOR]cm; p=0.26). The pattern of change in muscle blood volume from the initial to second set of intervals was significantly different (p<0.05) when the leg was active in the initial (-52.3 ± 111.6%) compared with second set (65.1 ± 152.9%). These data indicate that the order in which each leg performs sequential single-leg cycling influences the local hemodynamic responses, with the inactive muscle influencing the stimulus experienced by the contralateral leg.

  18. Using AAV vectors expressing the β2-adrenoceptor or associated Gα proteins to modulate skeletal muscle mass and muscle fibre size

    Science.gov (United States)

    Hagg, Adam; Colgan, Timothy D.; Thomson, Rachel E.; Qian, Hongwei; Lynch, Gordon S.; Gregorevic, Paul

    2016-01-01

    Anabolic β2-adrenoceptor (β2-AR) agonists have been proposed as therapeutics for treating muscle wasting but concerns regarding possible off-target effects have hampered their use. We investigated whether β2-AR-mediated signalling could be modulated in skeletal muscle via gene delivery to the target tissue, thereby avoiding the risks of β2-AR agonists. In mice, intramuscular administration of a recombinant adeno-associated virus-based vector (rAAV vector) expressing the β2-AR increased muscle mass by >20% within 4 weeks. This hypertrophic response was comparable to that of 4 weeks’ treatment with the β2-AR agonist formoterol, and was not ablated by mTOR inhibition. Increasing expression of inhibitory (Gαi2) and stimulatory (GαsL) G-protein subunits produced minor atrophic and hypertrophic changes in muscle mass, respectively. Furthermore, Gαi2 over-expression prevented AAV:β2-AR mediated hypertrophy. Introduction of the non-muscle Gαs isoform, GαsXL elicited hypertrophy comparable to that achieved by AAV:β2-AR. Moreover, GαsXL gene delivery was found to be capable of inducing hypertrophy in the muscles of mice lacking functional β1- and β2-ARs. These findings demonstrate that gene therapy-based interventions targeting the β2-AR pathway can promote skeletal muscle hypertrophy independent of ligand administration, and highlight novel methods for potentially modulating muscle mass in settings of disease. PMID:26972746

  19. Using AAV vectors expressing the β2-adrenoceptor or associated Gα proteins to modulate skeletal muscle mass and muscle fibre size.

    Science.gov (United States)

    Hagg, Adam; Colgan, Timothy D; Thomson, Rachel E; Qian, Hongwei; Lynch, Gordon S; Gregorevic, Paul

    2016-03-14

    Anabolic β2-adrenoceptor (β2-AR) agonists have been proposed as therapeutics for treating muscle wasting but concerns regarding possible off-target effects have hampered their use. We investigated whether β2-AR-mediated signalling could be modulated in skeletal muscle via gene delivery to the target tissue, thereby avoiding the risks of β2-AR agonists. In mice, intramuscular administration of a recombinant adeno-associated virus-based vector (rAAV vector) expressing the β2-AR increased muscle mass by >20% within 4 weeks. This hypertrophic response was comparable to that of 4 weeks' treatment with the β2-AR agonist formoterol, and was not ablated by mTOR inhibition. Increasing expression of inhibitory (Gαi2) and stimulatory (GαsL) G-protein subunits produced minor atrophic and hypertrophic changes in muscle mass, respectively. Furthermore, Gαi2 over-expression prevented AAV:β2-AR mediated hypertrophy. Introduction of the non-muscle Gαs isoform, GαsXL elicited hypertrophy comparable to that achieved by AAV:β2-AR. Moreover, GαsXL gene delivery was found to be capable of inducing hypertrophy in the muscles of mice lacking functional β1- and β2-ARs. These findings demonstrate that gene therapy-based interventions targeting the β2-AR pathway can promote skeletal muscle hypertrophy independent of ligand administration, and highlight novel methods for potentially modulating muscle mass in settings of disease.

  20. Recent advances for measurement of protein synthesis rates, use of the 'Virtual Biopsy' approach, and measurement of muscle mass.

    Science.gov (United States)

    Hellerstein, Marc; Evans, William

    2017-05-01

    Flux-rate measurements of protein synthesis and breakdown (turnover) in muscle represent an ideal class of mechanism-based biomarkers for conditions of altered muscle mass and function. We describe here new metabolic labeling techniques for flux-rate measurements in humans, focusing on skeletal muscle. Dynamics of the muscle proteome are accurately measured in humans by combining long-term heavy water labeling with tandem mass spectrometry. Broad proteomic flux signatures or kinetics of targeted proteins are measurable. After interventions, early fractional synthesis rates of skeletal muscle proteins predict later changes in muscle mass. The 'virtual biopsy' method for measuring tissue protein turnover rates from body fluids has been validated for skeletal muscle, from labeling of plasma creatine kinase-type M or carbonic anhydrase-3. Label in these proteins in plasma reflects label of cognate proteins in the tissue, and response in plasma predicts longer term outcomes. Skeletal muscle mass can also be measured noninvasively from a spot urine, based on dilution of labeled creatine. This method correlates well with whole body MRI assessment of muscle mass and predicts clinical outcomes in older men. Flux measurements are available and more interpretable functionally than static measurements for several reasons, which are discussed.

  1. Protein needs in athletes and dietary-nutrition guidelines to gain muscle mass

    Directory of Open Access Journals (Sweden)

    Aritz Urdampilleta

    2014-05-01

    Full Text Available One of the most important effects of strength training is muscular hypertrophy. Athletes should optimize their nutritional management in order to compensate their own genetic limitations. The aim of this review is to analyze the scientific evidence concerning protein intake as a tool to achieve muscle hypertrophy. Depending on the expenditure and energy intake of athlete, a daily protein ranging between 10-15% of total dietary intake is needed. However in sports diets, it is preferable to estimate the amount of protein needed per kilogram of body weight in each individual. In this regard athletes should ingest an amount between 1.2 g and 1.8 g of proteins/kg of body mass/day to maintain their lean mass. In order to increase muscle mass (0.5 kg/week, athletes should take between 1.6 g and 1.8 g of protein/kg/day with an increase of 400-500 kcal in their daily diet. These needs will depend on the sport, muscular catabolic status, the athlete’s lean mass and glycogen stores. Protein needs will increase if muscle and liver glycogen stores are empty. Excess of protein intake (more than 2 g/kg/day, with full glycogen stores, does not benefit the athlete and could cause an increase in circulating ketones and urea, thereby producing an early dehydration.

  2. Mass dynamics of wintering Pacific Black Brant: Body, adipose tissue, organ, and muscle masses vary with location

    Science.gov (United States)

    Mason, D.D.; Barboza, P.S.; Ward, D.H.

    2007-01-01

    We compared body size and mass of the whole body, organs, adipose tissue, and muscles of adult Pacific Black Brant (Branta bernicla nigricans (Lawrence, 1846)) collected concurrently in Alaska and Baja California during the fall, winter, and spring of 2002–2003. Head and tarsal lengths of males were similar between sites and slightly larger for females in Alaska than in Baja California. Brant appear to operate under similar physiological bounds, but patterns of nutrient allocation differ between sites. Birds wintering in Alaska lost similar amounts of adipose tissue during early winter as birds in Baja California gained during late winter before migration. Masses of the body, adipose tissue, and flight muscles during mid-winter were similar between sites. Seasonal adipose tissue deposition may, therefore, equally favor winter residency or long-distance migration. Gonad and liver masses increased in late winter for birds in Alaska but not for those in Baja California, suggesting birds wintering in Baja may delay reproductive development in favor of allocating reserves needed for migration. Phenotypic flexibility allows Brant to use widely divergent wintering sites. The wintering location of Brant likely depends more upon changes in environmental conditions and food availability, than upon physiological differences between the two wintering populations.

  3. Passive leg movement enhances interstitial VEGF protein, endothelial cell proliferation, and eNOS mRNA content in human skeletal muscle

    DEFF Research Database (Denmark)

    Hellsten, Ylva; Rufener, Nora; Nielsen, Jens J

    2008-01-01

    were analyzed for mRNA content of VEGF, endothelial nitric oxide synthase (eNOS), and matrix metalloproteinase-2 (MMP-2). The passive leg movement caused an increase (P ... to cultured endothelial cells revealed that dialysate obtained during leg movement induced a 3.2-fold higher proliferation rate (P MMP-2 mRNA levels were......The present study used passive limb movement as an experimental model to study the effect of increased blood flow and passive stretch, without enhanced metabolic demand, in young healthy male subjects. The model used was 90 min of passive movement of the leg leading to a 2.8-fold increase (P

  4. Broken Leg

    Science.gov (United States)

    ... the leg, which can result in a fracture. Stress fractures outside of sport situations are more common in people who have: ... shoes. Choose the appropriate shoe for your favorite sports or activities. And ... can prevent stress fractures. Rotate running with swimming or biking. If ...

  5. Insulin Treatment Attenuates Decline of Muscle Mass in Japanese Patients with Type 2 Diabetes.

    Science.gov (United States)

    Bouchi, Ryotaro; Fukuda, Tatsuya; Takeuchi, Takato; Nakano, Yujiro; Murakami, Masanori; Minami, Isao; Izumiyama, Hajime; Hashimoto, Koshi; Yoshimoto, Takanobu; Ogawa, Yoshihiro

    2017-07-01

    Sarcopenia is defined as an age-related loss of skeletal muscle mass and strength, and is a major cause of disability and mobility limitations. Recent studies have demonstrated that type 2 diabetes and insulin signaling deficiencies contribute to the progression of sarcopenia, suggesting that a sufficient supply of insulin to the skeletal muscles may be important for the maintenance of muscle function; however, little has been reported regarding whether insulin treatment can protect against sarcopenia. We conducted a retrospective observational study to examine the impact of insulin treatment on the muscle mass of patients with type 2 diabetes. A total of 312 patients (mean age: 64 ± 11 years; 40.8% female; 27.6% treated with insulin) were studied in this retrospective observational study. Skeletal muscle index (SMI) and grip strength (kg) were used to assess sarcopenia. The prevalence of sarcopenia was 18.0%. Insulin treatment was shown to be protective against the annual decline of SMI (standardized β 0.195; p = 0.025) even after adjusting for covariates, including age, gender, duration of diabetes, and body mass index. In a cohort matched by propensity scores, insulin treatment significantly increased the 1-year change in SMI (mean ± SE) compared with non-insulin-treated group (2.40 ± 0.98% vs. -0.43 ± 0.98%; p = 0.050). Our data suggest that insulin treatment could attenuate the progression of sarcopenia in patients with type 2 diabetes.

  6. Ultrasonographic evaluation of the calf muscle mass and architecture in elderly patients with and without sarcopenia.

    Science.gov (United States)

    Kuyumcu, Mehmet Emin; Halil, Meltem; Kara, Özgür; Çuni, Bledjan; Çağlayan, Gökhan; Güven, Serdar; Yeşil, Yusuf; Arık, Güneş; Yavuz, Burcu Balam; Cankurtaran, Mustafa; Özçakar, Levent

    2016-01-01

    To sonographically assess the muscle mass and architecture of sarcopenic elderly subjects, and to explore the utility of ultrasound (US) measurements in predicting sarcopenia. One hundred elderly subjects were enrolled in this cross-sectional study. Mean age value of our study population was 73.08±6.18years. The diagnosis of sarcopenia was confirmed by measuring fat-free mass index (using bioelectrical impedance analysis) and handgrip strength. Calf circumference was measured and US evaluations comprised bilateral gastrocnemius muscle (MG) thickness, fascicle length and pennate angles; subcutaneous fat and dermis thicknesses in the calf. Bilateral muscle thickness and fascicle length values were significantly lower in patients with sarcopenia (both pcalf. Bilateral MG thickness and fascicle length values showed high sensitivity in predicting sarcopenia (all values>76.92%). Gastrocnemius muscle thickness and fascicle length values are lower in sarcopenic elderly and these two parameters can serve as alternative measurements for predicting/quantifying sarcopenia. Calf circumference measurements alone may not be appropriate for assessing sarcopenia. Instead, US imaging can conveniently be used to evaluate different compartments of the musculoskelal system in (sarcopenic) elderly. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  7. MALDI imaging mass spectrometry of Pacific White Shrimp L. vannamei and identification of abdominal muscle proteins.

    Science.gov (United States)

    Schey, Kevin L; Hachey, Amanda J; Rose, Kristie L; Grey, Angus C

    2016-06-01

    MALDI imaging mass spectrometry (IMS) has been applied to whole animal tissue sections of Pacific White Shrimp, Litopenaeus vannamei, in an effort to identify and spatially localize proteins in specific organ systems. Frozen shrimp were sectioned along the ventral-dorsal axis and methods were optimized for matrix application. In addition, tissue microextraction and homogenization was conducted followed by top-down LC-MS/MS analysis of intact proteins and searches of shrimp EST databases to identify imaged proteins. IMS images revealed organ system specific protein signals that highlighted the hepatopancreas, heart, nervous system, musculature, and cuticle. Top-down proteomics identification of abdominal muscle proteins revealed the sequence of the most abundant muscle protein that has no sequence homology to known proteins. Additional identifications of abdominal muscle proteins included titin, troponin-I, ubiquitin, as well as intact and multiple truncated forms of flightin; a protein known to function in high frequency contraction of insect wing muscles. The combined use of imaging mass spectrometry and top-down proteomics allowed for identification of novel proteins from the sparsely populated shrimp protein databases. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Semimembranosus muscle herniation: a rare case with emphasis on muscle biomechanics

    Energy Technology Data Exchange (ETDEWEB)

    Naffaa, Lena [American University of Beirut, Department of Diagnostic Radiology, P.O. Box 11-0236, Riad El-Solh, Beirut (Lebanon); Moukaddam, Hicham [Saint Rita Medical Center, Lima, OH (United States); Samim, Mohammad [New York University, Department of Radiology, Hospital for Joint Disease, New York, NY (United States); Lemieux, Aaron [University of California, San Diego School of Medicine, La Jolla, CA (United States); Smitaman, Edward [University of California, San Diego, Teleradiology and Education Center, San Diego, CA (United States)

    2017-03-15

    Muscle herniations are rare and most reported cases involve muscles of the lower leg. We use a case of muscle herniation involving the semimembranosus muscle, presenting as a painful mass in an adolescent male after an unspecified American football injury, to highlight a simple concept of muscle biomechanics as it pertains to muscle hernia(s): decreased traction upon muscle fibers can increase conspicuity of muscle herniation(s) - this allows a better understanding of the apt provocative maneuvers to employ, during dynamic ultrasound or magnetic resonance imaging, in order to maximize diagnostic yield and, thereby, limit patient morbidity related to any muscle herniation. Our patient subsequently underwent successful decompressive fasciotomy and has since returned to his normal daily activities. (orig.)

  9. Semimembranosus muscle herniation: a rare case with emphasis on muscle biomechanics

    International Nuclear Information System (INIS)

    Naffaa, Lena; Moukaddam, Hicham; Samim, Mohammad; Lemieux, Aaron; Smitaman, Edward

    2017-01-01

    Muscle herniations are rare and most reported cases involve muscles of the lower leg. We use a case of muscle herniation involving the semimembranosus muscle, presenting as a painful mass in an adolescent male after an unspecified American football injury, to highlight a simple concept of muscle biomechanics as it pertains to muscle hernia(s): decreased traction upon muscle fibers can increase conspicuity of muscle herniation(s) - this allows a better understanding of the apt provocative maneuvers to employ, during dynamic ultrasound or magnetic resonance imaging, in order to maximize diagnostic yield and, thereby, limit patient morbidity related to any muscle herniation. Our patient subsequently underwent successful decompressive fasciotomy and has since returned to his normal daily activities. (orig.)

  10. Muscle cramps

    Science.gov (United States)

    ... the lower leg/calf Back of the thigh (hamstrings) Front of the thigh (quadriceps) Cramps in the ... Names Cramps - muscle Images Chest stretch Groin stretch Hamstring stretch Hip stretch Thigh stretch Triceps stretch References ...

  11. Proteome-wide muscle protein fractional synthesis rates predict muscle mass gain in response to a selective androgen receptor modulator in rats.

    Science.gov (United States)

    Shankaran, Mahalakshmi; Shearer, Todd W; Stimpson, Stephen A; Turner, Scott M; King, Chelsea; Wong, Po-Yin Anne; Shen, Ying; Turnbull, Philip S; Kramer, Fritz; Clifton, Lisa; Russell, Alan; Hellerstein, Marc K; Evans, William J

    2016-03-15

    Biomarkers of muscle protein synthesis rate could provide early data demonstrating anabolic efficacy for treating muscle-wasting conditions. Androgenic therapies have been shown to increase muscle mass primarily by increasing the rate of muscle protein synthesis. We hypothesized that the synthesis rate of large numbers of individual muscle proteins could serve as early response biomarkers and potentially treatment-specific signaling for predicting the effect of anabolic treatments on muscle mass. Utilizing selective androgen receptor modulator (SARM) treatment in the ovariectomized (OVX) rat, we applied an unbiased, dynamic proteomics approach to measure the fractional synthesis rates (FSR) of 167-201 individual skeletal muscle proteins in triceps, EDL, and soleus. OVX rats treated with a SARM molecule (GSK212A at 0.1, 0.3, or 1 mg/kg) for 10 or 28 days showed significant, dose-related increases in body weight, lean body mass, and individual triceps but not EDL or soleus weights. Thirty-four out of the 94 proteins measured from the triceps of all rats exhibited a significant, dose-related increase in FSR after 10 days of SARM treatment. For several cytoplasmic proteins, including carbonic anhydrase 3, creatine kinase M-type (CK-M), pyruvate kinase, and aldolase-A, a change in 10-day FSR was strongly correlated (r(2) = 0.90-0.99) to the 28-day change in lean body mass and triceps weight gains, suggesting a noninvasive measurement of SARM effects. In summary, FSR of multiple muscle proteins measured by dynamics of moderate- to high-abundance proteins provides early biomarkers of the anabolic response of skeletal muscle to SARM. Copyright © 2016 the American Physiological Society.

  12. Peak muscle mass in young men and sarcopenia in the ageing male

    DEFF Research Database (Denmark)

    Nielsen, Morten Frost Munk; Nielsen, T L; Brixen, K

    2015-01-01

    -based reference data on lean body mass (LBM) in young men during the time of peak levels of GH/IGF-1 and testosterone and further to apply the reference data on a population-based sample of men aged 60-74 years to estimate the prevalence of sarcopenia. METHODS: This is a cross-sectional, population-based single...... of sarcopenia in men. INTRODUCTION: The ageing population increases the prevalence of sarcopenia. Estimation of normative data on muscle mass in young men during the peak of anabolic hormones is necessary for the diagnosis of sarcopenia in ageing males. The purposes of this study were to provide population...

  13. Muscle Mass, Strength, Mobility, Quality of Life, and Disease Severity in Ankylosing Spondylitis Patients: A Preliminary Study.

    Science.gov (United States)

    Kim, Seung Chan; Lee, Yeong Guk; Park, Si-Bog; Kim, Tae Hwan; Lee, Kyu Hoon

    2017-12-01

    To determine if there is muscle mass reduction in patients with ankylosing spondylitis (AS) compared to the general population and to examine the relationship between skeletal muscle mass, quality of life (QOL), strength, and mobility in patients with AS. A total of 30 AS patients were enrolled in this study. Skeletal muscle mass was measured by bioelectrical impedance analysis, and it was expressed as the skeletal muscle mass index (SMI). QOL was assessed using the EuroQOL (EQ-5D). To measure mobility, the modified Schöber test and chest expansion test were used. To measure grip strength as a measure of muscle strength, we used the hydraulic hand dynamometer. Additionally, we divided the patients into two groups according to the degree of X-ray finding and compared the differences between the two groups. There was no significant reduction in skeletal muscle mass in patients with AS compared to the general population. Also, there was no significant correlation between SMI and QOL. On the other hand, there was a significant positive correlation between SMI and mobility, and grip strength. A significant positive correlation was found between mobility and QOL. Additionally, there was a statistically significant difference in mobility between the two groups according to the degree of X-ray finding. Maintaining muscle mass in AS patients may not be helpful for improving QOL, but it may contribute to achieving adequate mobility and strength.

  14. Muscle mass, isokinetic torque, and functional capacity in women with osteoarthritis of the knee.

    Science.gov (United States)

    Gür, Hakan; Cakin, Nilgün

    2003-10-01

    To investigate the relations between cross-sectional area and concentric and eccentric torques in the quadriceps and hamstring muscles and to determine how functional capacity relates to pain, muscle mass, and concentric and eccentric knee torques in women who have bilateral osteoarthritis (OA) of the knee. Randomized, descriptive study. A university exercise physiology laboratory in Turkey. Eighteen women with bilateral knee OA (grades 2 or 3) graded radiographically. Not applicable. Selected functional tests included the 15-m walk, rising from a chair, descending stairs, and stair climbing. Pain during the functional tests was subjectively measured on an 11-point scale (range, 0-10). Concentric and eccentric torques of the quadriceps and hamstring muscles were measured by isokinetic dynamometry with angular velocities of 60 degrees, 120 degrees, and 180 degrees /s; cross-sectional areas of the quadriceps and hamstring muscles were measured by computed tomography. Eccentric torque was significantly (P range, quadriceps (range, 16%-100%) and hamstring (range, 50%-158%) muscles at all angular velocities. Torque-velocity curves for concentric and eccentric contractions were almost identical to those found in healthy young and elderly people. According to r(2) values, cross-sectional area of the quadriceps and hamstring muscles explained 24% to 61% (r(2) range,.24-.61) and 38% to 51% (r(2) range,.38-.51) of the variations in concentric and eccentric peak torques, respectively. Very small to moderate correlations (.01-.75) were observed among torque at any velocity and the variables of functional capacity and pain. For stair-climbing times, the best predictor variable was the eccentric hamstring to concentric quadriceps torque ratio. For stair descending, it was the concentric hamstring to eccentric quadriceps torque ratios. These torque ratios explained 81% (r(2)=.81) and 61% (r(2)=.61) of the variations, respectively. The findings in a patient group with bilateral OA

  15. Dystrophic calcification in muscles of legs in calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly, and telangiectasia syndrome: Accurate evaluation of the extent with (99m)Tc-methylene diphosphonate single photon emission computed tomography/computed tomography.

    Science.gov (United States)

    Chakraborty, Partha Sarathi; Karunanithi, Sellam; Dhull, Varun Singh; Kumar, Kunal; Tripathi, Madhavi

    2015-01-01

    We present the case of a 35-year-old man with calcinosis, Raynaud's phenomenon, esophageal dysmotility, sclerodactyly and telangiectasia variant scleroderma who presented with dysphagia, Raynaud's phenomenon and calf pain. (99m)Tc-methylene diphosphonate bone scintigraphy was performed to identify the extent of the calcification. It revealed extensive dystrophic calcification in the left thigh and bilateral legs which was involving the muscles and was well-delineated on single photon emission computed tomography/computed tomography. Calcinosis in scleroderma usually involves the skin but can be found in deeper periarticular tissues. Myopathy is associated with a poor prognosis.

  16. Weight lifting and appendicular skeletal muscle mass among breast cancer survivors: a randomized controlled trial.

    Science.gov (United States)

    Brown, Justin C; Schmitz, Kathryn H

    2015-06-01

    Low appendicular skeletal muscle mass (ASMM) is associated with premature mortality, hyperinsulinemia, frailty, disability, and low bone mineral density. We explored the potential efficacy of slowly progressive weight lifting to attenuate the decline of ASMM among breast cancer survivors by conducting a post hoc analysis of data from the Physical Activity and Lymphedema trial. Between October 2005 and August 2008, we conducted a single-blind, randomized controlled trial of twice weekly slowly progressive weight lifting or standard care among 295 non-metastatic breast cancer survivors. ASMM was quantified using dual-energy X-ray absorptiometry. Changes in ASMM were evaluated from baseline to 12 months between the weight lifting and control groups using repeated measures linear mixed effects regression models. Over 12 months, participants in the weight lifting group experienced attenuated declines in muscle mass compared to the control group, as reflected by relative ASMM (-0.01 ± 0.02 kg/m(2) vs -0.08 ± 0.03 kg/m(2); P = 0.041) and absolute ASMM (-0.02 ± 0.06 kg vs -0.22 ± 0.07 kg; P = 0.038), respectively. Weight lifting did not alter other body composition outcomes including body mass index, total body mass, body fat percentage, and fat mass compared to the control group. Weight lifting significantly increased upper and lower body muscle strength compared to the control group. The intervention was well tolerated with no serious adverse events related to weight lifting. Slowly progressive weight lifting attenuated the decline of ASMM among breast cancer survivors compared to standard care over 12 months. These data are hypothesis generating. Future studies should examine the efficacy of weight lifting to improve distal health outcomes among breast cancer survivors.

  17. Time-Course of Muscle Mass Loss, Damage, and Proteolysis in Gastrocnemius following Unloading and Reloading: Implications in Chronic Diseases.

    Directory of Open Access Journals (Sweden)

    Alba Chacon-Cabrera

    Full Text Available Disuse muscle atrophy is a major comorbidity in patients with chronic diseases including cancer. We sought to explore the kinetics of molecular mechanisms shown to be involved in muscle mass loss throughout time in a mouse model of disuse muscle atrophy and recovery following immobilization.Body and muscle weights, grip strength, muscle phenotype (fiber type composition and morphometry and muscle structural alterations, proteolysis, contractile proteins, systemic troponin I, and mitochondrial content were assessed in gastrocnemius of mice exposed to periods (1, 2, 3, 7, 15 and 30 days of non-invasive hindlimb immobilization (plastic splint, I cohorts and in those exposed to reloading for different time-points (1, 3, 7, 15, and 30 days, R cohorts following a seven-day period of immobilization. Groups of control animals were also used.Compared to non-exposed controls, muscle weight, limb strength, slow- and fast-twitch cross-sectional areas, mtDNA/nDNA, and myosin content were decreased in mice of I cohorts, whereas tyrosine release, ubiquitin-proteasome activity, muscle injury and systemic troponin I levels were increased. Gastrocnemius reloading following splint removal improved muscle mass loss, strength, fiber atrophy, injury, myosin content, and mtDNA/nDNA, while reducing ubiquitin-proteasome activity and proteolysis.A consistent program of molecular and cellular events leading to reduced gastrocnemius muscle mass and mitochondrial content and reduced strength, enhanced proteolysis, and injury, was seen in this non-invasive mouse model of disuse muscle atrophy. Unloading of the muscle following removal of the splint significantly improved the alterations seen during unloading, characterized by a specific kinetic profile of molecular events involved in muscle regeneration. These findings have implications in patients with chronic diseases including cancer in whom physical activity may be severely compromised.

  18. Time-Course of Muscle Mass Loss, Damage, and Proteolysis in Gastrocnemius following Unloading and Reloading: Implications in Chronic Diseases

    Science.gov (United States)

    Chacon-Cabrera, Alba; Lund-Palau, Helena; Gea, Joaquim; Barreiro, Esther

    2016-01-01

    Background Disuse muscle atrophy is a major comorbidity in patients with chronic diseases including cancer. We sought to explore the kinetics of molecular mechanisms shown to be involved in muscle mass loss throughout time in a mouse model of disuse muscle atrophy and recovery following immobilization. Methods Body and muscle weights, grip strength, muscle phenotype (fiber type composition and morphometry and muscle structural alterations), proteolysis, contractile proteins, systemic troponin I, and mitochondrial content were assessed in gastrocnemius of mice exposed to periods (1, 2, 3, 7, 15 and 30 days) of non-invasive hindlimb immobilization (plastic splint, I cohorts) and in those exposed to reloading for different time-points (1, 3, 7, 15, and 30 days, R cohorts) following a seven-day period of immobilization. Groups of control animals were also used. Results Compared to non-exposed controls, muscle weight, limb strength, slow- and fast-twitch cross-sectional areas, mtDNA/nDNA, and myosin content were decreased in mice of I cohorts, whereas tyrosine release, ubiquitin-proteasome activity, muscle injury and systemic troponin I levels were increased. Gastrocnemius reloading following splint removal improved muscle mass loss, strength, fiber atrophy, injury, myosin content, and mtDNA/nDNA, while reducing ubiquitin-proteasome activity and proteolysis. Conclusions A consistent program of molecular and cellular events leading to reduced gastrocnemius muscle mass and mitochondrial content and reduced strength, enhanced proteolysis, and injury, was seen in this non-invasive mouse model of disuse muscle atrophy. Unloading of the muscle following removal of the splint significantly improved the alterations seen during unloading, characterized by a specific kinetic profile of molecular events involved in muscle regeneration. These findings have implications in patients with chronic diseases including cancer in whom physical activity may be severely compromised. PMID

  19. Free leucine supplementation during an 8-week resistance training program does not increase muscle mass and strength in untrained young adult subjects.

    Science.gov (United States)

    Aguiar, Andreo Fernando; Grala, Alan Pablo; da Silva, Rubens Alexandre; Soares-Caldeira, Lúcio Flávio; Pacagnelli, Francis Lopes; Ribeiro, Alex Silva; da Silva, Douglas Kratki; de Andrade, Walquíria Batista; Balvedi, Mario Carlos Welin

    2017-07-01

    The purpose of this study was to examine the effects of free leucine supplementation on changes in skeletal muscle mass and strength during a resistance training (RT) program in previously untrained, young subjects. In a double-blind, randomized, placebo-controlled study, 20 healthy young (22 ± 2 years) participants were assigned to two groups: a placebo-supplement group (PLA, N = 10) or a leucine-supplement group (LEU, N = 10). Both groups underwent an 8-week hypertrophic RT program (2 days/week), consuming an equivalent amount of leucine (3.0 g/day in a single post-training dose) or placebo (cornstarch). Quadriceps muscle strength, cross-sectional area (CSA) of the vastus lateralis (VL), and rectus femoris (RF), as well as the habitual dietary intake were assessed before and after the 8-week intervention period. There was a similar improvement in muscle strength (Leg press, LEU: +33% vs. PLA: +37%; P > 0.05, and knee extension, LEU: +31% vs. PLA: 34%; P > 0.05) and CSA (VL, LEU: 8.9% vs. PLA: 9.6%; P > 0.05, and RF, LEU: +21.6% vs. PLA: + 16.4%; P > 0.05) in the both groups from pre- to post-training. In addition, there was no significant (P > 0.05) difference in daily dietary intake between the LEU and PLA groups before and after the intervention period. Free leucine supplementation (3.0 g/day post-training) does not increase muscle strength or CSA during RT in healthy young subjects consuming adequate dietary protein intake.

  20. Body mass index from age 15 years onwards and muscle mass, strength, and quality in early old age: findings from the MRC National Survey of Health and Development.

    Science.gov (United States)

    Cooper, Rachel; Hardy, Rebecca; Bann, David; Aihie Sayer, Avan; Ward, Kate A; Adams, Judith E; Kuh, Diana

    2014-10-01

    As more people live more of their lives obese, it is unclear what impact this will have on muscle mass, strength, and quality. We aimed to examine the associations of body mass index (BMI) from age 15 years onwards with low muscle mass, strength, and quality in early old age. A total of 1,511 men and women from a British birth cohort study with BMI measured at 15, 20, 26, 36, 43, 53, and 60-64 years and dual-energy x-ray absorptiometry scans at 60-64 years were included. Four binary outcomes identified those in the bottom sex-specific 20% of (a) appendicular lean mass (ALM) index (kilogram per square meter), (b) ALM residuals (derived from sex-specific models in which ALM (kilogram) = β0 + β1 height [meter] + β2 fat mass [kilogram]), (c) grip strength (kilogram), (d) muscle quality (grip strength [kilogram]/arm lean mass [kilogram]). Associations of BMI with each outcome were tested. Higher BMI from age 15 years was associated with lower odds of low ALM but higher odds of low muscle quality (per 1 SD increase in BMI at 36 years, odds ratio of low ALM residuals = 0.50 [95% CI: 0.43, 0.59], and muscle quality = 1.50 [1.29, 1.75]). Greater gains in BMI were associated with lower odds of low ALM index but higher odds of low muscle quality. BMI was not associated with grip strength. Given increases in the global prevalence of obesity, cross-cohort comparisons of sarcopenia need to consider our findings that greater gains in BMI are associated with higher muscle mass but not with grip strength and therefore with lower muscle quality. © The Author 2014. Published by Oxford University Press on behalf of The Gerontological Society of America.

  1. The effect of between-set rest intervals on the oxygen uptake during and after resistance exercise sessions performed with large- and small-muscle mass.

    Science.gov (United States)

    Farinatti, Paulo T V; Castinheiras Neto, Antonio G

    2011-11-01

    Between-set rest intervals (RIs) may influence accumulated fatigue, work volume, and therefore oxygen uptake (VO2) and energy expenditure (EE) during resistance training. The study investigated the effects of different RIs on VO2 and EE in resistance exercises performed with multiple sets and recruiting large and small-muscle mass. Ten healthy men performed 4 randomized protocols (5 sets of 10 repetitions with 15 repetition maximum workloads in either horizontal leg press [LP] or chest fly [CF] with an RI of 1 and 3 minutes). The VO2 was measured at rest, within sets, and during 90-minute postexercise recovery (excess postexercise oxygen consumption [EPOC]). The EE was estimated from VO2net (total VO2 - rest VO2). The VO2 increased in all protocols, being higher within the exercises and during EPOC in the LP than in the CF regardless of the RI. The 1-minute RI induced higher accumulated VO2 during LP (p EPOC lasted approximately 40 minutes after LP1, LP3, and CF1, being longer than after CF3 (20 minutes, p CF1 = 50.3 ± 14.4 kcal ∼ CF3 = 54.1 ± 12.0 kcal). In conclusion, total VO2 was always higher in LP than in CF. Shortening RI enhanced the accumulated fatigue throughout sets only in LP and increased VO2 in the initial few minutes of EPOC, whereas it did not influence total VO2 and EE in both exercises. Therefore, (a) the role of RI in preventing early fatigue seems to be more important when large-muscle groups are recruited; (b) resistance exercises recruiting large-muscle mass induce higher EE because of a greater EPOC magnitude.

  2. Loss of Muscle Mass During Chemotherapy Is Predictive for Poor Survival of Patients With Metastatic Colorectal Cancer

    NARCIS (Netherlands)

    Blauwhoff-Buskermolen, Susanne; Versteeg, Kathelijn S.; de van der Schueren, Marian A. E.; den Braver, Nicole R.; Berkhof, Johannes; Langius, Jacqueline A. E.; Verheul, Henk M. W.

    2016-01-01

    Low muscle mass is present in approximately 40% of patients with metastatic colorectal cancer (mCRC) and may be associated with poor outcome. We studied change in skeletal muscle during palliative chemotherapy in patients with mCRC and its association with treatment modifications and overall

  3. Skeletal muscle mass and quality as risk factors for postoperative outcome after open colon resection for cancer

    NARCIS (Netherlands)

    Boer, B. C.; de Graaff, F.; Brusse-Keizer, M.; Bouman, D. E.; Slump, C. H.; Slee-Valentijn, M.; Klaase, J. M.

    The prevalence of colorectal cancer in the elderly is increasing and, therefore, surgical interventions with a risk of potential complications are more frequently performed. This study investigated the role of low skeletal muscle mass (sarcopenia), muscle quality, and the sarcopenic obesity as

  4. Effects of cessation of a structured and supervised exercise conditioning program on lean mass and muscle strength in severely burned children.

    Science.gov (United States)

    Suman, Oscar E; Herndon, David N

    2007-12-01

    To determine whether the benefits of exercise by burned children are maintained 3 months after the exercise program is concluded. Randomized, controlled prospective study. Pediatric burn hospital. Twenty severely burned children with a 40% or greater total body surface area burn, with main outcome measures completed before exercise training, immediately after 12 weeks of exercise training (intervention), and 12 weeks after training ended. Randomization into a 12-week standard rehabilitation program at home (n=9) or a 12-week standard hospital rehabilitation program supplemented with an exercise-training program beginning 6 months after burn injury (n=11). Assessment of lean body mass (LBM) using dual-energy x-ray absorptiometry and of leg isokinetic muscle strength at a speed of 150 degrees /s were done before, after the 12-week rehabilitation and exercise training program, and 3 months after the exercise program was completed (12mo postburn). The effects of exercise on the dependent variables were analyzed by repeated-measures analysis of variance. If we found a significant overall effect of time and/or intervention, we did a post hoc test for multiple comparison (Holm-Sidak). Results are expressed as mean +/- standard error. The mean percentage increase in LBM and muscle strength was significantly greater in the exercise group (6.4%+/-1.9%, 40.7%+/-8.6%, respectively) than in the no-exercise group (1.9%+/-2.6% vs 3.4%+/-4.5%, respectively). Three months after cessation of the exercise program, LBM remained relatively unchanged in the no-exercise group (3.5%+/-1.8%). In contrast, LBM in the exercise group increased significantly (10.7%+/-4.8%, P=.03). In addition, muscle strength further increased by 17.9%+/-10.1% in the exercise group versus 7.2%+/-3.4% in the no-exercise group, although neither percentage increase was significant (P=.08 for exercise vs P=.61 for no exercise). Absolute values in LBM and muscle strength for both groups at 12 months postburn

  5. Efficacy of phosphatidic acid ingestion on lean body mass, muscle thickness and strength gains in resistance-trained men

    Directory of Open Access Journals (Sweden)

    Hoffman Jay R

    2012-10-01

    Full Text Available Abstract Background Phosphatidic acid (PA has been reported to activate the mammalian target of rapamycin (mTOR signaling pathway and is thought to enhance the anabolic effects of resistance training. The purpose of this pilot study was to examine if oral phosphatidic acid administration can enhance strength, muscle thickness and lean tissue accruement during an 8-week resistance training program. Methods Sixteen resistance-trained men were randomly assigned to a group that either consumed 750 mg of PA (n = 7, 23.1 ± 4.4 y; 176.7 ± 6.7 cm; 86.5 ± 21.2 kg or a placebo (PL, n = 9, 22.5 ± 2.0 y; 179.8 ± 5.4 cm; 89.4 ± 13.6 kg group. During each testing session subjects were assessed for strength (one repetition maximum [1-RM] bench press and squat and body composition. Muscle thickness and pennation angle were also measured in the vastus lateralis of the subject’s dominant leg. Results Subjects ingesting PA demonstrated a 12.7% increase in squat strength and a 2.6% increase in LBM, while subjects consuming PL showed a 9.3% improvement in squat strength and a 0.1% change in LBM. Although parametric analysis was unable to demonstrate significant differences, magnitude based inferences indicated that the Δ change in 1-RM squat showed a likely benefit from PA on increasing lower body strength and a very likely benefit for increasing lean body mass (LBM. Conclusions Results of this study suggest that a combination of a daily 750 mg PA ingestion, combined with a 4-day per week resistance training program for 8-weeks appears to have a likely benefit on strength improvement, and a very likely benefit on lean tissue accruement in young, resistance trained individuals.

  6. Circulating 20S Proteasome Is Independently Associated with Abdominal Muscle Mass in Hemodialysis Patients

    Science.gov (United States)

    Fukasawa, Hirotaka; Kaneko, Mai; Niwa, Hiroki; Matsuyama, Takashi; Yasuda, Hideo; Kumagai, Hiromichi; Furuya, Ryuichi

    2015-01-01

    Protein-energy wasting is highly prevalent in hemodialysis patients, and it contributes to patient morbidity and mortality. The ubiquitin-proteasome system is the major pathway for intracellular protein degradation and it is involved in the regulation of basic cellular processes. However, the role of this system in the determination of nutritional status is largely unknown. To examine a relationship between protein-energy wasting and the ubiquitin-proteasome system, a cross-sectional study of 76 hemodialysis patients was performed. Plasma concentrations of 20S proteasome were studied to evaluate its association with muscle and fat mass, which were investigated by abdominal muscle and fat areas measured using computed tomography and by creatinine production estimated using the creatinine kinetic model. Plasma 20S proteasome concentrations significantly and negatively correlated with abdominal muscle areas and creatinine production (rho = -0.263, P hemodialysis patients. Our findings indicate a relationship between circulating 20S proteasomes and muscle metabolism in these patients. Trial Registration UMIN Clinical Trials Registry UMIN000012341 PMID:25803510

  7. Determination of Sulfonamides in Chicken Muscle by Pulsed Direct Current Electrospray Ionization Tandem Mass Spectrometry.

    Science.gov (United States)

    Fu, Xian; Liang, Hengxing; Xia, Bing; Huang, Chunyan; Ji, Baocheng; Zhou, Yan

    2017-09-20

    A simple and rapid approach for the simultaneous detection of trace amounts of six sulfonamides in chicken muscle was developed using pulsed direct current electrospray ionization tandem mass spectrometry (pulsed-dc ESI-MS/MS). The pretreatment of chicken muscle samples consisted of two steps: acetonitrile extraction and n-hexane delipidation. Sulfonamides do not need to be derivatized or chromatographed prior to pulsed-dc ESI-MS/MS. The factors affecting the performance of pulsed-dc ESI-MS/MS were studied. Under optimum conditions, the quantitative performance of pulsed-dc ESI-MS/MS was validated according to European Union Decision 2002/657/EC, and the sensitivity of pulsed-dc ESI-MS/MS was 3 times higher than that of ultrahigh-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The limits of detection obtained by pulsed-dc ESI-MS/MS were in the range of 0.07-0.11 μg/kg. The proposed method was simple, rapid, and sensitive, and was successfully used for quantitation and rapid screening of sulfonamides in real chicken muscle samples.

  8. Skeletal muscle mass adjusted by height correlated better with muscular functions than that adjusted by body weight in defining sarcopenia

    OpenAIRE

    Han, Der-Sheng; Chang, Ke-Vin; Li, Chia-Ming; Lin, Yu-Hong; Kao, Tung-Wei; Tsai, Keh-Sung; Wang, Tyng-Grey; Yang, Wei-Shiung

    2016-01-01

    Sarcopenia, characterized by low muscle mass and function, results in frailty, comorbidities and mortality. However, its prevalence varies according to the different criteria used in its diagnosis. This cross-sectional study investigated the difference in the number of sarcopenia cases recorded by two different measurement methods of low muscle mass to determine which measurement was better. We recruited 878 (54.2% female) individuals aged over 65 years and obtained their body composition and...

  9. SUN-P297 - Minerals and sarcopenia; the role of calcium, iron, magnesium, phosphorus, potassium, selenium, sodium, and zinc on muscle mass, muscle strength, and physical performance in older adults : a systematic review

    NARCIS (Netherlands)

    van Dronkelaar, D.C.; van Velzen, Aafke; Abdelrazek, Maya; van der Steen, A.; Weijs, P.J.M.; Tieland, C.A.B.

    Rationale: Minerals may contribute to prevent and treat sarcopenia, the age-related loss of muscle mass, muscle strength, and physical performance. The aim of this systematic review is to evaluate the role of calcium, iron, magnesium, phosphorus, potassium, selenium, sodium, and zinc on muscle mass,

  10. Variation of the Surface of the Longissimus Dorsi (LD Muscle and the Section of the Leg of Mutton at Young Sheep of Different Breed Structures

    Directory of Open Access Journals (Sweden)

    Elena Ilişiu

    2010-10-01

    Full Text Available The research was done on carcasses from the slaughter of young male sheep intensively fattened belonging to the local Tsigai race of mountain ecotype and its half-breeds with Suffolk and German blackface (GCCN. The purpose of the research was to determine Logissimus dorsi (LD and leg of moutton area, because these parts provide information on Ist meat quality. Research results have noted that lots of half-breeds achieved higher Longissimus dorsi (LD and leg of moutton area, compared with the pure breed batch. Compared with Tsigai breed, Longissimus dorsi (LD area deterrmined was higher with 10,75% to Suffolk x Tsigai half-breeds, and 0,07% respectively to German Blackface x Tsigai half-breeds. Leg of moutton area was higher with 17,27% to Suffolk x Tsigai halfbreeds, and 2,75% respectively to German Blackface x Tsigai half-breeds. Research carried out special information on Ist